Compound

ABSTRACT

The instant invention relates to sulphamate compounds of formula I, wherein A represents a ring structure, B represents a ring structure, D a ring structure, C is a bond, E is a link joining ring structure B to the ring structure D, X represents a suitable first group, and Y represents a suitable second group; wherein one ring of the compound is a phenolic ring; and wherein any one of ring structures A, B and D has bound thereto a sulphamate group.

RELATED APPLICATIONS

This application is a divisional of allowed U.S. application Ser. No. 09/638,315, filed Aug. 14, 2000, now U.S. Pat. No. 6,506,792, as a continuation-in-part of allowed U.S. apllication Ser. No. 09/238,345, filed Jan. 27, 1999, now U.S. Pat. No. 6,187,266 which was a division of U.S. application Ser. No. 09/111,927, filed Jul. 8, 1998, now U.S. Pat. No. 6,011,024, which in turn was a continuation-in-part of inter alia PCT patent application No. PCT/GB97/00600, filed Mar. 4, 1997, designating the U.S. and claiming priority from United Kingdom patent applications 9604709.7 and 9605725.2, filed Mar. 5 and 19, 1996, respectively. PCT/GB97/00600 was published as WO 97/32872 on Sep. 12, 1997. U.S. application Ser. No. 09/142,194, filed Sep. 2, 1998 as the National Phase (35 USC 371) of PCT/GB97/00600 is now U.S. Pat. No. 6,083,978. Each of these applications and patents and each document cited or referenced in each of these applications and patents, including during any prosecution (“application cited documents”), and each document cited or referenced in each of the application cited documents, are hereby incorporated herein by reference. In addition, each document cited in this text (“herein cited documents”) and each document cited or referenced in each of the herein cited documents, are hereby incorporated herein by reference.

The present invention relates to a compound.

In particular the present invention relates to a pharmaceutical composition comprising the compound.

Breast and endometrial cancers are major causes of death in Western women. In particular, tumours in endocrine-dependent tissues, such as the breast and endometrium, occur most frequently in postmenopausal women at a time when the ovaries have ceased their production of oestrogens.

Evidence suggests that oestrogens are the major mitogens involved in stimulating and promoting the growth of tumours in endocrine-dependent tissues, such as the breast and endometrium²¹. Although plasma oestrogen concentrations are similar in women with or without breast cancer, breast tumour oestrone and oestradiol levels are significantly higher than in normal breast tissue or blood. In addition, in postmenopausal women oestrogens continue to be produced by extraglandular production in adipose tissue but also in normal and malignant breast tissues²².

FIGS. 1 and 2 are schematic diagrams showing some of the enzymes involved in the in situ synthesis of oestrone from oestrone sulphate, oestradiol and androstenedione.

In FIG. 2, which schematically shows the origin of oestrogenic steroids in postmenopausal women, “ER” denotes Oestrogen Receptor, “DHA/-S” denotes Dehydroepiandrosterone/-Sulphate, “Adiol” denotes Androstenediol, “E1-STS” denotes Oestrone Sulphatase, “DHA-STS” denotes DHA-sulphatase, “Adiol-STS” denotes Adiol Sulphatase, and “17B-HSD” denotes Oestradiol 17B-hydroxysteroid dehydrogenase.

As can be seen, the main two enzymes that are involved in the peripheral systhesis of oestrogens are the aromatase enzyme and the enzyme oestrone sulphatase.

In short, the aromatase enzyme converts androstenedione, which is secreted in large amounts by the adrenal cortex, to oestrone. Recent reports have suggested that some flavones could inhibit aromatase activity^(35,36).

Much of the oestrone so formed, however, is converted to oestrone sulphate (E1S) and there is now a considerable body of evidence showing that E1S in plasma and tissue acts as a reservoir for the formation of oestrone by the action of oestrone sulphatase²³.

In this regard, it is now believed that the oestrone sulphatase (E1-STS) pathway—i.e. the hydrolysis of oestrone sulphate to oestrone (E1S to E1) is the major source of oestrogen in breast tumours^(1,2). This theory is supported by a modest reduction of plasma oestrogen concentration in postmenopausal women with breast cancer treated by aromatase inhibitors, such as aminoglutethimide and 4-hydroxyandrostenedione^(3,4) and also by the fact that plasma E1S concentration in these aromatase inhibitor-treated patients remains relatively high. The long half-life of E1S in blood (10–12 h) compared with the unconjugated oestrogens (20 min)⁵ and high levels of steroid sulphatase activity in liver and, normal and malignant breast tissues, also lend support to this theory⁶.

Thus, oestrogen formation in malignant breast and endometrial tissues via the sulphatase pathway makes a major contribution to the high concentration of oestrogens which are present in these tumours^(24,25).

PCT/GB92/01587 teaches novel steroid sulphatase inhibitors and pharmaceutical compositions containing them for use in the treatment of oestrone dependent tumours, especially breast cancer. These steroid sulphatase inhibitors are sulphamate esters, such as N,N-dimethyl oestrone-3- sulphamate and, preferably, oestrone-3-sulphamate (otherwise known as “EMATE”).

EMATE is a potent E1-STS inhibitor as it displays more than 99% inhibition of E1-STS activity in intact MCF-7 cells at 0.1 μM. EMATE also inhibits the E1-STS enzyme in a time-dependent and concentration-dependent manner, thereby indicating that it acts as an active site-directed inactivator^(7,8).

Although EMATE was originally designed for the inhibition of E1-STS, it also inhibits dehydroepiandrosterone sulphatase (DHA-STS), which is an enzyme that is believed to have a pivotal role in regulating the biosynthesis of the oestrogenic steroid androstenediol^(8,9). This is of significance as there is now evidence to suggest that androstenediol may be of even greater importance as a promoter of breast tumour growth¹⁰.

EMATE is also active in vivo as almost complete inhibition of rat liver E1-STS (99%) and DHA-STS (99%) activities resulted when it is administered either orally or subcutaneously¹¹. In addition, EMATE has been shown to have a memory enhancing effect in rats¹⁴. Studies in mice have suggested an association between DHA-STS activity and the regulation of part of the immune response. It is thought that this may also occur in humans^(15,16). The bridging O-atom of the sulphamate moiety in EMATE is believed to be important for inhibitory activity. Thus, when the 3-O-atom is replaced by other heteroatoms—as in oestrone-3-N-sulphamate and oestrone-3-S-sulphamate—these analogues are weaker non-time-dependent inactivators¹².

Thus, EMATE is a potent steroid sulphatase inhibitor which blocks the hydrolysis of both E1S and DHA-S²⁹⁻³¹. This inhibitor, therefore, not only blocks the synthesis of oestrone from E1S but also the formation of androstenediol from DHA-S.

In addition to oestrone, the other major steroid with oestrogenic properties which is produced by postmenopausal women is androstenediol (see FIG. 2). Androstenediol, although an androgen, can bind to the oestrogen receptor (ER) and can stimulate the growth of ER positive breast cancer cells and the growth of carcinogen-induced mammary tumours in the rat^(26,27). Importantly, in postmenopausal women 90% of the androstenediol produced originates from the androgen dehydroepiandrosterone sulphate (DHA-S) which is secreted in large amounts by the adrenal cortex. DHA-S is converted to DHA by DHA sulphatase, which may be the same as, or different from, the enzyme, oestrone sulphatase, which is responsible for the hydrolysis of E1S²⁸.

During the last 10–15 years considerable research has also been carried out to develop potent aromatase inhibitors, some of which are currently undergoing clinical evaluation. However, in three recent reports of postmenopausal women with breast cancer who received aromatase inhibitor therapy, plasma E1S concentrations remained between 400–1000 pg/ml³²⁻³⁴.

In summation therefore in situ synthesis of oestrogen is thought to make an important contribution to the high levels of oestrogens in tumours and therefore specific inhibitors of oestrogen biosynthesis are of potential value for the treatment of endocrine-dependent tumours.

Moreover, even though oestrogen formation in malignant breast and endometrial tissues via the sulphatase pathway makes a major contribution to the high concentration of oestrogens, there are still other enzymatic pathways that contribute to in vivo synthesis of oestrogen.

Thus, there is an urgent need to develop new therapies for the treatment of these cancers.

The present invention therefore seeks to overcome one or more of the problems associated with the prior art methods of treating breast and endometrial cancers.

According to a first aspect of the present invention there is provided a sulphamate compound suitable for use as an inhibitor of both oestrone sulphatase activity and aromatase activity.

In a highly preferred embodiment, the compound of the present invention is a non-steroidal compound.

According to a second aspect of the present invention there is provided a compound having the general formual II wherein F represents a phenolic ring structure (a first ring structure), J represents a third ring structure, I represents a phenolic ring structure (a second ring structure), G is an optional double bond, H is a link joining the second ring structure to the thrid ring structure, and Y represents a suitable second group; wherein any one of ring structures F, J and I has bound thereto a sulphamate group.

According to a third aspect of the present invention there is provided a compound according to the present invention for use as a pharmaceutical.

According to a fourth aspect of the present invention there is provided a compound according to the present invention for inhibiting oestrone sulphatase activity and aromatase activity.

According to a fifth aspect of the present invention there is provided a pharmaceutical composition comprising a compund according to the present invention, and a pharmaceutically acceptable carrier, excipient or diluent.

According to a sixth aspect of the present invention there is provided the use of a compound according to the present invention in the maufacture of a pharmaceutical for inhibiting oestrone sulphatase activity and aromatase activity.

According to a seventh aspect of the present invention there is provided a process for preparing a compound according to the present invention, the process comprising sulphating a flavone, isoflavone or a flavanone.

According to an eighth aspect of the present invention there is provided a process for preparing a compound according to the present invention, the process comprising sulphamaylating a flavone, isoflavone or a flavanone.

In one aspect, therefore, the present invention provides a compound, or a pharmaceutical composition comprising the same, that can affect, such as substantially inhibit, not only the oestrone sulphatase pathway—which pathway converts oestrone to and from oestradiol—but also the aromatase pathway—which pathway converts the androgen precursor androstenedione to oestrone.

This aspect of the present invention is advantageous because by the administration of one type of compound it is possible to block the synthesis of oestrone from both androstenedione and E1S.

In addition, the present invention is further advantageous in that it may also be possible to block the formation of androstenediol from DHA-S.

Hence, the present invention provides compounds that have considerable therapeutic advantages, particularly for treating breast and endometrial cancers.

The compounds of the present invention are different from those disclosed in the prior art because they can act as therapeutic agents that possess both aromatase and steroid sulphatase inhibitory properties.

In a preferred embodiment the compound of the present invention comprises a first ring structure and a sulphamoyl group, which first ring structure may be substituted and/or unsaturated.

Preferably the first ring structure is a phenolic ring structure, which phenolic ring may be substituted.

Preferably, the compound of the present invention further comprises a second ring structure, which second ring structure may be substituted and/or unsaturated.

Preferably the second ring structure is a phenolic ring structure, which phenolic ring may be substituted.

Preferably, the compound of the present invention further comprises a third ring structure which is intermediate the first ring structure and the second ring structure, which third ring structure may be substituted and/or unsaturated.

The present invention will now be described by reference to the Formulae presented in FIGS. 3–9.

In this regard, its is generally preferred that the compound of the present invention has the general formula I wherein A represents the first ring structure, B represents the third ring structure, D represents the second ring structure, C is an optional double bond, E is a link joining the second ring structure to the third ring structure, X represents a suitable first group, and Y represents a suitable second group; wherein any one of ring structures A, B and D is a phenolic ring; and wherein any one of ring structures A, B and D has bound thereto a sulphamate group.

Each of the ring structures can independently comprise from 3 and 20 atoms in the ring, preferably from 4 to 8 atoms in the ring. Preferably, ring A and ring D comprise 6 atoms in the ring.

Preferably, the first ring structure and the second ring structure are substituted.

Preferably, any one of ring structures A and D has bound thereto a sulphamate group.

Preferably, each of the first ring and the second ring is a homogeneous ring structure—i.e. the ring is made up of the same atoms.

Preferably, each of the first ring and the second ring comprises only carbon atoms in the ring.

X may be C or C═O. Preferably, X is C═O.

Preferably, the compound of the present invention has the general formula II wherein F represents a phenolic ring structure (the first ring structure), J represents the third ring structure, I represents a phenolic ring structure (the second ring structure), G is an optional double bond, H is a link joining the second ring structure to the third ring structure, and Y represents a suitable second group; wherein any one of ring structures F, J and I has bound thereto a sulphamate group.

Preferably, the third ring structure is a heterogeneous ring structure—i.e. different atoms are in the ring.

Y may be N (including NH, substituted N), C (including CH₂, substituted C), O, or S. Preferably, Y is O.

Preferably any one of the ring structures F and I has bound thereto a sulphamate group.

Preferably, link E or link H is a bond.

Preferably, the compound of the present invention is a sulphamate of any one of a flavone, an isoflavone or a flavanone.

Preferably, the compound of the present invention is any one of a compound of the general formula IV, a compound of the general formual V, or a compound of the general formual VI; wherein R₁–R₁₂ are independently selected from H, OH, a halogen, an amine, an amide, a sulphonamine, a sulphonamide, any other sulphur containing group, a saturated or unsaturated C₁₋₁₀ alkyl, an aryl group, a saturated or unsaturated C₁₋₁₀ ether, a saturated or unsaturated C₁₋₁₀ ester, a phosphorous containing group; and wherein at least one of R₁–R₁₂ is a sulphamate group.

Preferably, the sulphamate group has the general formula OSO₂NR₁₃R₁₄ wherein R₁₃ and R₁₄ are independently selected from H, OH, a halogen, a saturated or unsaturated C₁₋₁₀ alkyl, an aryl group, a saturated or unsaturated C₁₋₁₀ ether, a saturated or unsaturated C₁₋₁₀ ester.

Preferably, the compound of the present invention is any one of a compound of the general formula IV, a compound of the general formula V, or a compound of the general formula VI; wherein R₁–R₁₂ are independently selected from H, OH, OSO₂NR₁₃R₁₄, O—CH₃; wherein at least one of R₁–R₁₂ is OSO₂NR₁₃R₁₄, and wherein R₁₃ and R₁₄ are defined as above.

Preferably, at least one of R₁₃ and R₁₄ is H. Preferably, each of R₁₃ and R₁₄ is H.

Preferably, the compound of the present invention is a sulphamate of any one of the flavone of formula VII, the isoflavone of formula VIII, or the flavanone of formula IX.

Preferably, the compound of the present invention is the sulphamate of any one of formula VII, formula VIII or formula IX.

Preferably, the compound of the present invention is a sulphamate of any one of a flavone, an isoflavone or a flavanone; and wherein the sulphamoyl group is on the C4′ atom of the flavone, isoflavone or flavanone. The C4′ position has been shown in general Formula III according to the present invention.

Preferably, the compound of the present invention is a flavonoid or flavanoid sulphamate.

In summation the present invention provides compounds that avoid the need for polytherapy. In this regard, the compounds of the present invention can act as therapeutic agents that possess both aromatase and steroid suplhatase inhibitory properties.

Preferably, if the sulphamate group of the compound of the present invention were to be replaced with a sulphate group so as to form a sulphate compound then that sulphate compound would be hydrolysable by an enzyme having steroid sulphatase (E.C. 3.1.6.2) activity.

The compound of the present invention may have one or more sulphamate groups. For example, the compound may be a mono-sulphamate or a bis-sulphamate. For example, in FIGS. 7, 8 and 9 R₃ and R₄ may be each a sulphamate.

FIGS. 1 and 2 present schematic pathways; FIGS. 3–10 present chemical formulae; and FIG. 11 presents a graph.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 present schematic pathways

FIGS. 3–10 present chemical formulae

FIG. 11 presents a graph

FIG. 12 presents a structure of oestrone and oestrone-3-O-sulphamate (EMATE)

FIG. 13 presents a structure of flavonoids

FIG. 14 presents a general method of sulphamolyation

The present invention will now be described only by way of example.

COMPOUNDS SYNTHESISED

The following sulphamate derivatives were synthesised from the following parent compounds:

PARENT SULPHAMATE COMPOUND COMPOUND 1 2 3 4 5 6 7 8 9 10 wherein

-   -   1=6-hydroxy flavone     -   2=flavone-6-sulphamate     -   3=7-hydroxy flavone     -   4=flavone-7-sulphamate     -   5=5,7-dihydroxy flavone     -   6=5-hydroxy-flavone-7-sulphamate     -   7=5,7-dihydroxy-4′-hydroxy-flavone     -   8=5,7-dihydroxy flavanone-4′-flavanone sulphamate     -   9=5,7-dihydroxy-4′-methoxy-isoflavone     -   10=5-hydroxy-4′-methoxy-isoflavone-isoflavone-7-sulphamate

The formulae are presented in FIGS. 7–9.

SYNTHESIS

The sulphamate derivatives were prepared essentially as described previously²⁹. In this regard, a solution of the appropriate flavone, isoflavone or flavanone in anhydrous DMF was treated with sodium hydride (60% dispersion; 1 equiv for 2 and 4; 2 equiv for 6, 8 and 10) at 0° C. under an atmosphere of N₂. After evolution of hydrogen has ceased, sulfamoyl chloride (2 equiv except for 8.5 equiv) was added and the reaction mixture was poured into brine after warming to room temperature overnight and diluting with ethyl acetate. The organic fraction was washed exhaustively with brine, dried (MgSO₄), filtered and evaporated. The crude product obtained was purified by flash chromatography and recrystallisation to give the corresponding sulfamate.

Flavone 6-O-sulphamate (2)

6-Hydroxyflavone (1.0 g, 4.113 mmol) gave crude product (1.21 g) which was fractionated on silica (200 g) with ethyl acetate. Upon evaporation, the first fraction gave a creamy residue (760 mg, 58.2%) which was recrystallised in warm acetone/hexane (3:2) to give 2 as creamy rod-shaped crystals (557 mg); m.p. 190–191° C.; R_(f)s=0.71 (ethyl acetate), 0.51 (ethyl acetate/hexane, 2:1), vmax (KBr) 3260, 3040, 1620, 1600, 1580, 1370, 1180 cm⁻¹; δ_(H) (acetone-d₆) 6.917 (1H, s, C-3-H), 7.355 (2H, br s, exchanged with D₂O, —OSO—NH), 7.64 (3H, m, C-3′-H, C-4′-H and C-5′-H), 7.75 (1H, dd, J_(C-3-H, C-7-H)=9 Hz and J_(C-5-H, C-7-H)=3 Hz, C-7-H), 7.87 (1H, d, J_(C-7-H, C-8-H)=9 Hz, C-8-H), 8.02 (1H, d, J_(C-7-H, C-5-H)=3 Hz, C-5-H) and 8.13 (2H, m, C-2′-H and C-6′-H). MS: m/z (E.I., rel. intensity) 317.0(11), 304.2(6), 238.0(96), 210.0(16), 187.1(14), 152.0(8), 136.0(100). Acc. MS (E.I): m/z 317.0296, C₁₅H₁₁NO₅S requires 317.0358. Found C, 56.7; H, 3.44; N, 4.31, C₁₅H₁₁NO₅S requires C, 56.78; H, 3.49; N, 4.41%.

Flavone 7-O-sulphamate (4)

7-Hydroxyflavone (700 mg, 2.938 mmol) gave crude product (770 mg) which was fractionated on silica (200 g) with ethyl acetate. Upon evaporation, the first fraction gave a light brown residue (132 mg) which was recrystallised in hot isopropyl alcohol to give 4 as white needle-shaped crystals (60 mg), m.p. 172–174° C. (dec.); R_(f)s=0.78 (ethyl acetate), 0.56 (ethyl acetate/hexane, 4.1); vmax (KBr) 3260, 3100, 1630, 1600, 1400, 1580, 1200, 1150 cm⁻¹; δ_(H) (DMSO-d₆/CDCl₃, ca. 1:20) 6.824 (1H, s, C-3-H), 7.396 (1H, dd, J_(C-5-H, C-6-H)=8.8 Hz and J_(C-8-H, C-6-H)=2.2 Hz, C-6-H), 7.47 (2H, br s, exchanged with D₂O, —OSO₂NH ₂), 7.55 (3H, m, C-3′-H, C-4′-H and C-5′-H), 7.639 (1H, d, J_(C-6-H, C-8-H)=2.2 Hz, C-8-H), 7.92 (2H, m, C-2′-H and C-6′-H) and 8.220 (1H, d, J_(C-6-H, C-5-H)=8.8 Hz, C-5-H). Found: C, 56.5; H, 3.36; N, 4.19, C₁₅H₁₁NO₅S requires C, 56.78; H, 3.49; N, 4.41%.

5-Hydroxyflavone 7-O-Sulphamate (6)

5,7-Dihydroxyflavone (1.0 g, 3.933 mmol) gave crude product (1.13 g) which was fractionated on silica (200 g) with chloroform/acetone (8:1). Upon evaporation, the second fraction gave a yellow residue (324 mg, 24.7%) which was recrystallised in ethyl acetate/hexane (1:1) to give 6 as yellow crystals (213 mg), m.p. 195–200° C. (dec.); R_(f)s=0.21, 0.25 and 0.44 for chloroform/acetone 12:1, 8:1 and 4:1 respectively: vmax (KBr) 3360, 3250, 2925-2850, 1650, 1610, 1380 cm⁻¹, δ_(H) (acetone-d₆) 6.75, 6.98, 7.17 (3H, three s, C-3-H, C-6-H, C-8-H), 7.63 (2H, br s, exchanged with D₂O, —OSO-NH ₂), 7.65 (3H, m, C-3′-H, C-4′-H and C-5′-H), 8.15 (2H, d, J=7.7 Hz, C-2′-H and C-6′-H) and 13.0 (1H, br s, exchanged with D₂O, C-5-OH). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 440.1(10), 389.3(10), 334.1[100, (M+H)⁺], 288.1(17), 255.0[25, (M+H−79)⁺], 169.1(30). MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 499.0(30), 484.1[14, (M−2H+153 ⁻], 475.1(20), 443.1(24), 332.1[100, (M−H)⁻], 308.1(28), 274.1(20), 253.1[50, (M−H−79)⁻], 195.1(24). Acc. MS (+ve ion FAB in m-NBA): m/z 334.0392. C₁₅H₁₂NO₅S requires 334.0385. Found: C, 54.0; H, 3.39; N, 4.21. C₁₅H₁₁NO₆S requires C, 54.03; H, 3.33; N, 4.20%.

5,7-Dihydroxyflavanone 4′-O-sulphamate (8)

4′,5,7-Trihydroxyflavanone (1.0 g, 3.675 mmol) gave crude product (965 mg) which was fractionated on silica (200 g) with ethyl acetate/hexane (4:1) to give a mixture of the starting flavanone and product. This mixture was further fractionated on silica (200 g) with chloroform/acetone (4:1) and upon evaporation, the second fraction gave a pale yellow oil (345 mg, 34%) which solidified on standing. Subsequent recrystallisation of this solid in ethyl acetate/hexane (1:1) gave 8 as white crystals (259 mg), m.p. 211–213° C.; R_(f)=0.21 (chloroform/acetone, 4:1); vmax (KBr) 3420, 3340, 3260, 3140, 1640, 1510, 1380, 1160 cm⁻¹; δ_(H) (acetone-d₆) 2.84 (1H, dd, J_(AB)=17.4 Hz and J_(ax, eq)=3.1 Hz, C-3-H ₈), 3.19 (1H, dd, J_(BA)=16.9 Hz and J_(ax,ax)=12.8 Hz, C-3-H _(A)), 5.62 (1H, dd, J_(ax, eq)=3.1 Hz and J_(ax, ax)=12.8 Hz, C-2-H), 5.98 (1H, d, J=2.0 Hz, C-6-H or C-8-H), 6.01 (1H, d, J=2.0 Hz, C-6-H or C-8-H), 7.20 (2H, br s, exchanged with D₂O, —OSO₂NH ₂), 7.40 (2H, d, J=8.7 Hz, C-2′-H and C-6′-H), 7.66 (2H, d, J=8.7 Hz, C-3′-H and C-5′-H), 9.65 (1H, br s, C-7-OH) and 12.15 (1H, s, C-5-OH). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 352.0[100, (M+H)⁺], 288.1(10), 272.1[14, (M−79)⁻], 255.2(9), 169.0(13). MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 701.2(12), 606.2(10), 517.1(42), 504.1[20, (M+153)⁻], 473.2(10), 350.1[100, (M−H)⁻], 271.1[45, (M−H−79)⁻], 182.0(8). Acc. MS (+ve ion FAB in m-NBA): m/z 352.0496, C₁₅H₁₄NO₇S requires 352.0491. Found: C, 51.1; H, 3.68; N, 3.98. C₁₅H₁₃NO₇S requires C, 51.28; H, 3.73; N, 3.99%.

5-Hydroxy-4′-methoxyisoflavone 7′-O-sulphamate (10)

5,7-Dihydroxy-4′-methoxyisoflavone (800 mg, 2.817 mmol) gave crude product (650 mg) which was fractionated on silica (200 g) with chloroform/acetone (8:1). Upon evaporation, the second fraction gave a yellow residue (266 mg, 26%) which was recrystallised in ethyl acetate/hexane (1:1) to give 10 as yellow crystals (211 mg), m.p. 184–188° C.; R_(f)s=0.22 and 0.59 for chloroform/acetone 8:1 and 4:1 resepectively; vmax (KBr) 3300–3020, 1660, 1610, 1400 cm⁻¹; δ_(H) (acetone-d₆) 3.86 (3H, s, —OCH ₃), 6.75 (1H, d, J=2.2 Hz, C-6-H and C-8-H), 7.04 (3H, m, C-6-H or C-8-H and C-3′-H and C-5′-H), 7.49 (2H, br s, exchanged with D₂O, —OSO₂NH ₂), 7.58 (2H, d, J=7 Hz, C-2′-H and C-6′-H), 8.41 (1H, s, C-2-H), 13.05 (1H, br s, exchanged with D₂O, C-5-OH). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 393.3(12), 364.0[100, (M+H)⁺], 284.1[12, (M−79)⁺], 169.1(24), 134.0(22). MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 529.1(25), 515.1[12, (M−H+153)⁻], 442.1(20), 362.1[100, (M−H)⁻], 308.1(34), 283.1[70, (M−H−79)⁻], 170.1(26). Acc. MS (+ve ion FAB in m-NBA): m/z 364.0494, C₁₆H₁₄NO₇S requires 364.0491. Found: C, 52.8; H, 3.65; N, 3.81. C₁₆H₁₃NO₇S requires C, 52.89; H, 3.61; N, 3.85%.

5-Hydroxy Isoflavone-4′,7-O,O-Disulphamate (11) and 5,7-Dihydroxy Isoflavone-4′-O-Sulphamate (12)

4′,5,7-Trihydroxy isoflavone (0.5 g, 1.85 mmol) upon sulphamoylation gave a crude product (0.65 g) which was fractionated on silica (200 g) with chloroform/acetone (4:1), and upon evaporation the third fraction gave a light yellow residue (0.329 g, 51%) which was recrystallized in ethylacetate/hexane (1:2) to give compound (11) as beige crystals (0.197 g); m.p.=>198° C. (dec); R_(f)s=0.14 and 0.24 for chloroform/acetone 4:1 and 2:1 respectively; v^(max) (KBr) 3460 (—NH₂), 1650 (C═O), 1400 (—SO₂N—) cm⁻¹; δ_(H) (acetone-d₆) 6.78 (1H, d, J=2.2 Hz, C-6-H or C-8-H, 7.03 (1H, d, J=2.2 Hz, C-8-H or C-6-H), 7.4 (4H, br s, exchanged with D₂O, C-4′-OSO₂NH ₂ and C-7-OSO₂NH ₂), 7.43 (2H, d, J=8.4 Hz, C-3′-H and C-5′-H or C-2′-H and C-6′-H and C-6′-H), 7.72 (2H, d, J=8.4 Hz, C-2′-H and C-6′-H or C-3′-H and C-5′-H), 8.51 (1H, s, C-2-H) and 12.93 (1H, s, C-5-OH). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 428.9[100, (M+H)⁺], 350.0 [20, (M+H−SO₂NH₂)⁺], 272.1 [30, (M−H−SO₂NH₂)⁺]. MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 426.9 [100, (M−H)⁻], 347.9 [95, (M-H-SO₂NH₂)⁻], 269.0 [30, (M−H−SO₂NH₂)⁻]. Acc. MS: m/z (FAB)⁺ 429.0083 C₁₅H₁₃N₂O₉S₂ requires 429.0063. Found C, 42.0; H, 2.91; N, 6.45; C₁₅H₁₂N₂O₉S₂ requires C, 42.06; H, 2.82; N, 6.54%.

The second fraction was collected and upon evaporation gave light yellow residue (0.112 g, 17%) which was recrystallized in ethylacetate/hexane (1:3) to give compound (12) as pale white crystals (0.068 g); m.p.=189–192° C. R_(f)s=0.23 and 0.33 for chloroform/acetone 4:1 and 2:1 respectively; v^(max) (KBr) 3500–3300 (—NH₂), 3200 (H-bonded-OH), 1680 (C═O), 1610, 1400 (—SO₂N—)cm⁻¹; δ_(H) (acetone-d₆) 6.32 (1H, d, J=2.2 Hz, C-6-H or C-8-H), 6.46 (1H, d, J=2.2 Hz, C-8-H or C-6-H), 7.32 (2H, br s, exchanged with D₂O,—SO₂NH ₂), 7.42 (2H, t, J=8.4 Hz, C-3′-H and C-5′-H or C-2′-H and C-6′-H, 7.69 (2H, d, J=8.4 Hz, C-2′-H and C-6′-H or C-3′-H and C-5′-H), 8.31 (1H, s, C-2-H), 9.53 (1H, s, C-7-OH) and 12.9 (1H, s, C-5-OH). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 350.0 [100, (M+H)⁺], 271.1 [15, (M+H−SO₂NH₂)⁺]. MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 347.9 [100, (M−H)⁻], 269.0 [20, (M−H−SO₂NH₂)⁻]. Acc. MS: m/z (FAB)⁺ 350.0347 C₁₅H₁₂NO₇S requires 350.0335. Found C, 51.0; H, 3.16; N, 3.90; C₁₅H₁₁NO₇S requires C, 51.58; H, 3.17; N, 4.01%.

Isoflavone-4′,7-O,O-Disulphamate (13)

4′,7-Dihydroxy isoflavone (0.45 g, 1.77 mmol) upon sulphamoylation gave a crude product (0.769 g) which was fractionated on silica (200 g) with chloroform/acetone (4:1), and upon evaporation the second fraction gave a pale white residue (0.553 g, 72%) which was recrystallized in acetone/hexane (1:2) to give the compound (13) as white crystals (0.327 g); m.p.>195° C. (dec.); R_(f)s=0.21 and 0.40 for chloroform/acetone 4:1 and 2:1 respectively; v^(max) (KBr) 3400 (—NH₂), 1640 (C═O), 1360 (—SO₂N—) cm⁻¹. δ_(H) (DMSO-d₆), 7.37 (2H, d, J=8.8 Hz, C-3′-H and C-5′-H or C-2′-H and C-6′-H, 7.42 (1H, dd, J_(C-6-H, C-8-H)=2.2 Hz, J_(C-6-H, C-5-H)=8.8 Hz, C-6-H), 7.7 (2H, d, J=8.8 Hz, C-2′-H and C-6′-H or C-3′-H and C-5′-H), 8.09 (2H, br s, exchanged with D₂O, —OSO₂NH ₂), 8.24 (1H, d, J=8.8 Hz, C-5-H, 8.36 (2H, br s, exchanged with D₂O, —OSO₂NH ₂), 8.63 (1H, s, C-2-H). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 412.9 [100, (M+H)⁺], 334.0 [25, (M+H−SO₂NH₂)⁺], 255.1 [20, (M+H−SO₂NH₂)⁺]. MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 410.9 [100, (M−H)⁻], 332.0 (70, (M−H−SO₂NH₂)⁻], 253.0 [30, (M−H−SO₂NH₂)⁻]. Acc. MS: m/z (FAB)⁺ 413.0119 C₁₅H₁₃N₂O₈S₂ requires 413.0113. Found C, 44.0; H, 2.94; N, 6.62; C₁₅H₁₂N₂O₈S₂ requires C, 43.69; H, 2.93; N, 6.79%.

Assay of Inhibition of Sulphatase and Aromatase Activities

Sulphatase inhibition was assessed using placental microsome (100,000 g) preparations or intact MCF-7 breast cancer cells as described previously ^(29,30). Placental microsomes were incubated with ³H E1S, adjusted to 20 μM with unlabelled substrate, in the absence or presence of inhibitor.

Placental microsomes were also used to assess the aromatase inhibitory properties of the flavanoid sulphamates using a tritiated water release assay³⁷. Further placental microsomes (200 μl) were incubated with [1β-³H] androstenedione, 60 nM and 1 mM NADPH in the absence or presence of inhibitor.

Inhibition of Sulphatase and Aromatase Activities

Inhibition of oestrone sulphatase and aromatase activities in placental microsomes by the flavanoid sulphamate derivatives is shown in the Table below.

% % CONCENTRATION INHIBITION INHIBITION COMPOUND μM Sulphatase Aromatase Flavone-6- 1 26.8 1 sulphamate 10 89.5 6.5 Flavone-7- 1 — 55 sulphamate 10 — 86 50 56.3 100 75.3 5-hydroxy 1 8 5 flavone-7- 10 21 76 sulphamate 5,7-dihydroxy 0.1 30.4 Not tested flavanone 4′- 1 79.1 Not tested sulphamate 10 98.1 Not tested 5-hydroxy-4′- 1 1 2 methoxy- 10 50.6 5 isoflavone-7- sulphamate

From the results, it can be seen that potent inhibition of sulphatase and aromatase activities was detected. For sulphatase inhibition this ranged from 21% at 10 μM by 5-hydroxy flavone-7-sulphamate, to 98% by 5,7-dehydroxy flavanone-4′-sulphamate at 10 μM. Potent aromatase inhibition was also achieved ranging from 6.5% by flavone-6-sulphamate at 10 μM to 86% by flavone-7-sulphamate at 10 μM.

Further In Vitro Testing

The following Table presents in vitro data for three isoflavones that were tested.

IN VITRO ACTIVITY % Inhibition Concentration Placental Compound (μM) MCF-7 Cells Microsomes Isoflavone 5-hydroxy-4′,7- 0.1 28 nd bissulphamate 1.0 90 nd 10.0 99 93 Isoflavone 5,7-dihydroxy- 0.1 23 nd 4′-sulphamate 1.0 83 nd 10.0 99 75 Isoflavone-4′,7- 0.1 89 nd bissulphamate 1.0 99 nd 10.0 99 99 nd = not done In Vivo Testing

FIG. 11 presents in vivo inhibition of oestrone sulphatase activity in rat liver for two isoflavones according to the present invention. In this regard, BH22F1=5- hydroxy isoflavone-4′,7-bissulphamate; BH22BF1=5,7-dihydroxy isoflavone-4′-sulphamate. Compounds were administered as a single 10 mg/Kg dose. Oestrone sulphatase activity was assayed in tissue samples obtained 24 h after drug administration.

Compounds 14–16

Starting with the appropriate parent compound, the ring system sulphamates according to the present invention were prepared essentially as follows. In this regard, a solution of the appropriate parent compound in anhydrous DMF was treated with sodium hydride [60% dispersion; 1.2 equiv.] at 0° C. under an atmosphere of N₂. After evolution of hydrogen had ceased, sulfamoyl chloride in toluene [excess, ca. 5 equiv.] was added and the reaction mixture was poured into brine after warming to room temperature overnight and diluting with ethyl acetate. The organic fraction was washed exhaustively with brine, dried (MgSO₄), filtered and evaporated. The crude product obtained was purified by flash chromatography and recrystallisation to give the corresponding sulfamate. All the compounds were fully characterized by spectroscopic and combustion analysis.

Example compounds are as follows:

The following compounds of the present invention are made and are found to be steroid sulphatase inhibitors in accordance with the present invention.

The synthesis and biological activity of further compounds in accordance with the present invention are set out in Appendix I.

Various modifications and variations of the present invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are obvious to those skilled in chemistry, biology or related fields are intended to be within the scope of the following claims.

REFERENCES

(1) Santner, S. J.; Feil, P. D.; Santen, R. J. In situ oestrogen production via the oestrone sulphatase pathway in breast tumors: relative importance vs. the aromatase pathway. J. Clin. Endocrinol. Metab. 1984, 59, 29–33.

(2) Yamamoto, T.; Kitawaki, J.; Urabe, M.; Honjo, H.; Tamura, T.; Noguchi, T.; Okada, H.; Sasaki, H.; Tada, A.; Terashima, Y.; Nakamura, J.; Yoshihama, M. Oestrogen productivity of endometrium and endometrial cancer tissue—influence of aromatase on proliferation of endometrial cancer cells. J. Steroid Biochem. Mol. Biol. 1993, 44, 463–468.

(3) Santen, R. J.; Santner, S. J.; Davis, B.; Veldhuis, J.; Samojilik, E.; Ruby, E. Aminogluthethimide inhibits extraglandular oestrogen production in post-menopausal women with breast carcinoma. J. Clin. Endocrinol. Metab. 1978 47, 1257–1265.

(4) Reed, M. J.; Lai, L. C.; Owen, A. M.; Singh, A.; Coldham, N. G.; Purohit, A.; Ghilchik, M. W.; Shaikh, N. A.; James, V. H. T. Effect of treatment with 4-hydroxy-androstenedione on the peripheral conversion of androstenedione to oestrone and in vitro tumour aromatase activity in postmenopausal women with breast cancer. Cancer Res. 1990, 50, 193–196.

(5) Ruder, H. J.; Loriaux, D. L.; Lipsett, M. B. Oestrone sulphate: production rate and metabolism in man. J. Clin. Invest. 1972, 51, 1020–1023.

(6) James, V. H. T.; McNeill, J. M.; Lai, L. C.; Newton, C. J.; Ghilchik, M. W.; Reed, M. J. Aromatase activity in normal breast and breast tumor tissues: in vivo and in vitro studies. Steroids 1987, 50, 269–279.

(7) Howarth, N. M.; Purohit, A.; Reed, M. J.; Potter, B. V. L. Oestrone sulphamates: potent inhibitors of oestrone sulphatase with therapeutic potential. J. Med. Chem. 1994, 37, 219–221.

(8) Purohit, A.; Williams, G. J.; Howarth, N. M.; Potter, B. V. L.; Reed, M. J. Inactivation of steroid sulphatase by an active site-directed inhibitor, oestrone-3-O-sulphamate.

(9) Purohit, A.; Dauvois, S.; Parker, M. G.; Potter, B. V. L.; Williams, G. J.; Reed, M. J. The hydrolysis of estrone sulphate and dehydroepiandrosterone sulphate by human steroid sulphatase expressed in transfected COS-1 cells. J. Steroid Biochem. Mol. Biol. 1994, 50, 101–104.

(10) Dauvois, S.; Labrie, F. Androstenedione and androst-5-ene-3β,17β-diol stimulate DMBA-induced rat mammary tumours—role of aromatase. Breast Cancer Res. Treat. 1989, 13, 61–69.

(11) Purohit, A.; Williams, G. J.; Roberts, C. J.; Potter, B. V. L.; Reed, M. J. In vivo inhibition of oestrone sulphatase and dehydroepiandrosterone sulphatase by oestrone-3-O-sulphamate. Int. J. Cancer 1995, 63, 106–111.

(12) Woo, L. W. L.; Lightowler, M.; Purohit, A.; Reed, M. J.; Potter, B. V. L. Heteroatom-substituted analogues of the active-site directed inhibitor oestra-1,3,5(10)-trien-17-one-3-sulphamate inhibit oestrone sulphatase by a different mechanism. J. Steroid Biochem. Mol. Biol. 1996 (in press).

(13) Elger, W.; Schwarz, S.; Hedden, A.; Reddersen, G.; Schneider, B. Sulphamates of various oestrogens—prodrugs with increased systemic and reduced hepatic oestrogenicity at oral application. J. Steroid Biochem. Mol. Biol. 1995, 55, 395–403.

(14) Li, P. K.; Rhodes, M. E.; Jagannathan, S; Johnson, D. A. Memory enhancement mediated by the steroid sulphatase inhibitor oestrone 3-O-sulphamate. J. Endocrinol. 1995, 144, Abstr. P155.

(15) Daynes, R. A.; Araneo, B. A.; Dowell, T. A.; Huang, K.; Dudley, D. Regulation of murine lymphokine production in vivo. 3. The lymphoid tissue micro-environment exerts regulatory influences over T-helper cell function. J. Exp. Med. 1990, 171, 979–996.

(16) Rook, G. A. W.; Hernanadez-Pando, R.; Lightman, S. Hormones, peripherally activated prohormones and regulation of the TH1/TH2 balance. Immunol. Today 1994, 15, 301–303.

(21) James & Reed (1980) Prog Cancer Res Ther 14: 471–487.

(22) James et al (1987) Steroids 50: 269–279.

(23) Reed et al (1994) Drugs for the Future 19: 673–680.

(24) Santner et al (1984) J Clin Endocr Metab 59: 29–33.

(25) Yamamoto et al (1993) J Steroid Biochem Molec Biol 44: 463–468.

(26) Poulin & Labrie (1986) Cancer Res 46: 4933–4937.

(27) Dauvois & Labrie (1989) Breast Cancer Res Treat 13: 61–69.

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(29) Howarth et al (1994) J Med Chem 37: 219–221.

(30) Purohit et al (1995) Biochemistry 34: 11508–11514.

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(35) Kellis et al (1986) Biochem Pharmacol 35: 2887–2891.

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APPENDIX I

This appendix refers to the following figures

-   -   FIG. 12. Structure of Oestrone and Oestrone-3-O-sulphamate         (EMATE).     -   FIG. 13. Structure of Flavonoids.     -   FIG. 14. General Method of Sulphamolyation.

Flavonoid sulphamates 1–22 were prepared in an analogous fashion to other sulphamates described previously, as shown in FIG. 14. Briefly, a solution of the appropriate flavone, isoflavone or flavanone was treated in anhydrous DMF with sodium hydride (1.2 equiv. for monohydroxy compounds and 2.5 equiv. for dihydroxy compounds) at 0° C. (under N₂). Sulphamoyl chloride in toluene (excess, ca. 3 and 5 equiv. for monohydroxyl and dihydroxyl compounds respectively) was then added and after the mixture had warmed to room temperature overnight, the reaction was quenched with ethyl acetate. The crude product, after work up for each flavonoid sulphamate was purified by flash chromatography and recrystallisation. All compounds were fully characterized by spectroscopic and combustion analysis.

The yield of the sulphamates were improved significantly by using excess of sulphamoyl chloride (≧5 eq.).

Commercially unavailable (±) equol (22a) was prepared by the modified method of Wessely and Prillinger as described, and the structure was elucidated by ¹ _(H)NMR, ¹³ _(C)NMR, Mass spectroscopy and microanalysis for the first time.

A hydroxyl group at the 5-position of the flavonoids couldn't be sulphamoylated even by using excess of NaH. This was also confirmed by attempting to sulphamoylate 5-hydroxy-7-methoxy flavone (3a). The reaction didn't work and the only explaintion is that the formation of a complex between the sodium and the ketone group at the 4-position of the flavonoids, followed by the formation of the hydrogen bond between the proton of the hydroxyl group at the 5-position and the ketone group at the 4-position of the flavonoids when the reaction was quenched, as shown by ¹HNMR, the proton of the 5-position hydroxyl group was recorded at about 11–12 ppm (downfeild).

The stability of each sulphamate was found to be varied and influenced by different factors, such as conjugation and environmental conditions (functional groups in the sulphamate compounds, position of sulphamate group and pKa of the phenol). To establish the relationship between activity and stability, stability studies were carried out for selected flavonoid sulphamates 1, 2, 3, 16 and 20, both under the conditions of bioassay and also in methanol, using HPLC analysis. Stability studies of all flavonoid sulphamates have also been carried out in different solvents including methanol, acetone, tetrahydrofuran (THF) and ethanol using TLC.

Only the monosulphamate 20 could be obtained from 20a even by using 2.5 eq. of NaH, the bisulphamate was not formed or degraded due to lack of stability.

Biology

Inhibition of E1-STS in intact MCF-7 breast cancer cells and that of aromatase in placental microsomes by flavonoid sulphamates (1–22) is shown in Table 1.

TABLE I Inhibition of Oestrone Sulphatase and Aromatase Activities by Flavanoid Sulphamates. % Inhibition of % Inhibition of sulphatase aromatase activity in Compound activity in MCF-7 cells placental micro- No. 0.1 μM 1 μM 10 μM. somes at 10 μM. 1 0.30 ± 0.2 1.8 ± 1.0 4.9 ± 0.3 96 2 ND 99.1 ± 0.6 98.9 ± 1.3 14 3 ND 4.2 ± 0.9 20.6 ± 1.2 85 4 11 ± 2.7 51 ± 3.0 78 ± 1.7 * 5 35 ± 4.0 88 ± 3.1 99 ± 0.6 82 6 * 18 ± 6.1 27 ± 3.5 95 7 29 ± 0.8 23 ± 1.8 12 ± 0.5 * 8 * 13 ± 8.0 29 ± 1.3 * 9 8 ± 2.6 79 ± 0.8 98 ± 0.4 90 10 * 8 ± 6.4 12 ± 7.5 14 11 * * * * 12 * * * 39 13 * * * 38 14 * * * 22 15 * * * 35 16 * 11 ± 3.0 37 ± 1.7 * 17 28 ± 1.7 90 ± 0.6 99 ± 1.4 * 18 23 ± 2.2 83 ± 2.7 99 ± 0.7 * 19 87 ± 2.5 >99 >99 * 20 30 ± 2.8 79 ± 1.2 98 ± 1.2 85 21 2 ± 1.3 8 ± 0.6 9 ± 1.2 60 22 >99 >99 >99 13 23 * * * ND 24 18.4 ± 0.8 42.2 ± 1.3 95.3 ± 0.3 ND 25 14.9 ± 7   65.4 ± 1.2 96.2 ± 0.2 ND 26 99.6 ± 0.3 99.6 ± 0.4 99.1 ± 0.1 ND ND: not determined *Inactive

TABLE 2 Inhibition of oestrone Sulphatase in vivo for Flavanoid Sulphamates and EMATE as measured in rat liver, 24 hours after single oral dose in propylene glycol. NO. Compound Dosage % Inhibition 1b EMATE  1 mg/Kg >99 17 5-Hydroxy isoflavone-4′,7-O, 10 mg/Kg 81.4 ± 3.2 O-bisulphamate 18 5,7-Dihydroxy-4′-O-sulphamate 10 mg/Kg 62.0 ± 4.7 19 Isoflavone-4′,7-O,O-bisulphamate 10 mg/Kg 71.4 ± 2.9 20 5,7-Dihydroxy flavanone-4′-O- 10 mg/Kg 44.2 ± 3.8 sulphamate

The results can be summarized as follows: Most of these compounds significantly inhibited E1-STS in MCF-7 cells when added at a concentration of 10 μM. Compounds 17–20 are the most active in this series, with inhibitory activity about 99% in MCF-7 cells at 10 μM. However, in general, it was found that the isoflavone sulphamates 17–19 are more potent than flavone and flavanone sulphamates. It was also found that bisulphamates are more potent than the corresponding monosulphamate (e.g. 17 and 18).

The effect of a sulphamate group when attached to a non-aromatic ring (ring C of flavonoids) was also evaluated and found to be inactive (10–15), confirming that the phenyl ring structure is required for potent inhibition.

Discussion

In the last ten years, numerous reports have suggested the importance of oestrone sulphate and oestrone sulphatase in regulating the supply of oestrogens to oestrogen-dependent breast cancer. Thus, E1-STS inhibitors may prove to be useful for the treatment of breast cancers. We have already demonstrated that EMATE 1b is the most potent active-site directed irreversible inhibitor reported to date. However, due to the oestrogenic activity of EMATE there remains a real and substantial need for potent non-steroidal E1-STS inhibitors that are metabolically stable, more selective and devoid of oestrogenic activity.

Having identified the key chemical structural requirement for potent sulphatase inhibition (i.e. phenolic ring structure and —O-sulphamoyl group), we considered that introduction of the sulphamoyl group into the flavonoids structure might significantly engender sulphatase inhibitory activity and, might provide new lead for the design of a dual non-steroidal sulphatase/aromatase inhibitor as several flavonoids have aromatase inhibitory activity (REFs). We selected the flavonoid system for the following reasons: 1) Since EMATE is highly oestrogenic, there is a need to develop other classes of potential inhibitors. 2) Flavonoids are ubiquitous commercially available secondary plant metabolites and possess not only a phenolic ring structure (one of a key chemical structural requirements for potent sulphatase inhibition), which can potentially mimic the A ring of EMATE, but another phenyl ring which can also be (poly) hydroxylated. 3) Flavonoids are natural compounds, the vast majority of them are nontoxic to human and animals, and the known pharmacological activities are limited to a few substances of this group. 4) The low rate of incidence of breast cancer in the Far East, rather than genetic difference is an important factor, has been related to a high dietary intake of Soya products containing flavones and isoflavones. 5) It has been reported that several flavonoids are potent aromatase inhibitors and it is likely that sulphamates of these flavonoids will also inhibit the activity of this enzyme. 6) Recently it has also been reported that some flavonoids inhibited the enzyme 17β-hydroxysteroid dehydrogenase which converts oestrone to oestradiol the most biologically active oestrogen.

and 7) We have shown that the related coumarin ring system when sulphamoylated, can possess good E1-STS inhibition activity (REF).

Biological evaluation of the novel synthetic entities revealed that most of these flavonoid sulphamates (1–22) show potent sulphatase inhibitory properties at 10 μM in MCF-7 cells. Compounds (5, 17, 18 and 20) inhibited E1-STS in MCF-7 cells in ranges of 22–87% at 0.1 μM, 79–99% at 1 μM and >99% at 10 μM. The best inhibitor in this series, isoflavone-4′,7-O,O-bisulphamate (19), inhibited E1-STS activity in MCF-7 cells by 87% and >99% at 0.1 μM and 1 μM respectively.

Flavone-7-O-sulphamate, (1) was found to inhibit aromatase in placental microsomes by 86% at 10 μM. This result is encouraging as our approach of synthesizing flavonoid sulphamates may lead to the eventual development of dual aromatase/sulphatase inhibitors. However, we need to establish in future work if the inhibition of aromatase by (1) is actually an inherent property of the molecule or is the result of an in vivo activation of (1) to the potent known aromatase inhibitor, 7-hydroxyflavone (1c).

Many sulphamates were noticed to be only weakly stable or unstable at high temperature and in the more polar solvents and decomposed in DMF (reaction solvent). Therefore, by using a larger excess of sulphamoyl chloride (±5 eq.) than used the yield improved significantly.

However, to understand and imporve the relationship between the activity and stability of flavonoid sulphamates, stability studies were carried out by HPLC for some selective flavonoid sulphamates under the same conditions of biological assay and in methanol, and also by TLC in different solvents including methanol, acetone, tetrahydrofuran (THF) and ethanol. The following general results were noticed:

-   -   i) Most of the conjugated sulphamates (double bond in ring C of         flavonoids structure) were unstable and decomposed quickly to         their parent compounds in the biological medium and methanol.     -   ii) The presence of functional groups such as methoxy group,         hydroxy group and ketone group on the main ring of the         sulphamates structure increases the degradation of these         compounds.     -   iii) The sulphamates were found to be weakly stable and         decomposed slowly in acetone, but unstable and decomposed         rapidly in methanol, ethanol, and DMSO. Most of the sulphamates         were fairly stable in THF. Therefore, it is advisable when         possible to use THF to dissolve the compound for biological         assay to avoid potential degradation.     -   iv) All bis-sulphamates were found to be fairly stable in         solvents and in the biological medium and they decomposed to         corresponding monosulphamate parent compounds (e.g. 17, 18).     -   v) It was found that when the sulphamoyl group was present at         the 6-position of flavonoid sulphamates, the sulphamates were         more stable than if it was present at 7-position, e.g.         flavone-6-O-sulphamate 2 is more stable than         flavone-7-O-sulphamate 1. It also was found that when the         sulphamoyl group was present at the 4′-position of flavonoid         sulphamates it is more stable than if it is at 7-position. For         example, 5,7-dihydroxy flavanone-4′-O-sulphamate 20 is more         stable and has significant activity compared with the         7-O-sulphamates of flavonoids.

It was noticed that the stable sulphamates established significant activity, while the unstable compounds in the main show moderate or no activity.

These stability studies were able to guide us to introduce the sulphamoyl group at the most favorable position of flavonoids with respect to stability (i.e. 4′ of ring B of flavonoids structure) of sulphatase and aromatase inhibitors. We believe that the ketone group and the conjugation in ring C of flavonoids play major roles in reducing the stability, which affects negatively the inhibition of E1-STS activity. Therefore, to confirm this and to improve the stability of the potent isoflavone sulphamates (17–19), we have synthesized (±) 4′,7-dihydroxy flavane (equol) 22a and sulphamolyated it to get isoflavane 4′,7-O,O-bisulphamate 22 (22a was first recognized in 1932; our study is the first to provide modern spectroscopic data for this compound). This compound was found to be more stable in polar solvents than the corresponding isoflavone-4′,7-O,O-bisulphamate 19 as shown by a TLC study, but it is less potent for inhibition of E1-STS activity in MCF-7 and placental microsomes. Thus, we can say now that the presence of the ketone group at the 4-position of ring C in the flavonoid structure decreases stability but it is nevertheless essential for potent E1-STS inhibition activity, perhaps by contributing extra binding to the active site of the enzyme.

Further modifications need to be carried out in this series to improve both sulphatase and aromatase inhibitory activities significantly and to make the usually compounds completely devoid of oestrogenic activity, as it is known that some flavonoids are oestrogenic at high dose (REF).

Overall, this study has revealed that flavonoid sulphamates are a new class of potential E1-STS inhibitors and can establish significant inhibition of E1-STS activity. We have also provided preliminary evidence supporting the concept and novel idea of a dual sulphatase/aromatase inhibitor based upon the flavonoid system. More work is required to explore this goal, but some of the compounds reported here could be useful new leads.

CONCLUSION

This study has clearly demonstrated that the sulphamoyl group is essential for E1-STS inactivation, as most of these flavonoid sulphamates are potent and significantly inhibited E1-STS in MCF-7 cells when present at 10 μM or lower. Our data indicate that flavonoid sulphamates 2, 5, 9, 17–20 and 22 are potent sulphatase inhibitors which also possess aromatase inhibitory activity. These compounds therefore represent key lead compounds for optimization of potential dual sulphatase/aromatase inhibitors.

Flavonoid sulphamates may therefore be effective therapeutic agents in the treatment of oestrogen-dependent breast cancer, but it is crucial to be fully cognizant of inherent stability problems.

This observation opens the door for further studies to design and maximize metabolically stable potent dual sulphatase/aromatase inhibitors.

Experimental Section

Materials, Methods and Instruments Used

Chemistry

All reagents and solvents employed were of general purpose or analytical grade used without purification unless otherwise stated, and purchased from either Aldrich Chemicals or Lancaster Synthesis. Silica gel refers to silica gel 60, 230–400 mesh (MercK), and analytical TLC was performed on pre-coated plates (Merck TLC, aluminium sheets silica F₂₅₄. Art No. 5554) with detection by either UV light or using methanolic phosphomolybdic acid followed by heating. All Melting points were determined on Reichert-Jung Kofler block and are uncorrected. Microanalysis were performed with a Carlo Erba elemental analyzer (Model 1106) for C, H, N, IR, spectra were determined using KBr discs, using a Perkin-Elmer 782 Infra-Red Spectrophotometer and are expressed in cm⁻¹. The ¹HNMR spectra were recorded on a Jeol GX 270 at 270 MHz and on a Jeol EX 400 at 400 MHz; chemical shifts are reported in part per million (ppm) on the δ scale downfield relative to trimethylsilane as internal standard; coupling constants (J) are reported in hertz (Hz). The following abbreviations are used to describe resonances in ¹HNMR spectra, s=singlet; d=doublet; T=triplet; q=quartet; m=multiplet; br=broad and combination such as dd=doublet of doublets.

Mass spectra were recorded on VG 7070 and VG Autospec instruments. HPLC Stability studies were determined using LDC Constametric 3000 HPLC Pump and Spectrometer 3000 variable wave length detector.

All reagents and solvents used were stored away from moisture and light and dried before use. All organic extracts were dried over MgSO₄. Evaporation implies the removal of solvents by use of a rotary evaporator at 30–35° C. under vacuum (water pump) and on stated occasions, followed by the use of a high vacuum pump. The samples were dried in a drying tube at low temperature at reduced pressure.

Microanalysis were determined at the University of Bath

Stability Study by HPLC

A small amount of sulphamate was taken and dissolved in 1 ml methanol. Sulphamate methanolic solution (10%) was prepared by dissolving 100 μl of this solution in 900 μl phosphate buffer solution (PBS) at 37° C. The resulting solution was injected immediately into an HPLC. Samples were injected at 0, 5, 10, 20, 30, 60 and 120 min. (depending upon rate of degradation of sulphamate, the injection time was varied). The mobile phase used was 90%, 70%, 30% and 10%, but in recent studies 10% of methanol was used, and a low concentration of methanol as mobile phase (10%) is advisable to avoid the possibility of degradation of sulphamates by methanol. The flow rate was 1 ml/min. To select the optimum wavelength of absorptions by different sulphamates, the UV scan was checked between 200–350 nm. The wavelength of EMATE type compounds was at 270 nm.

As the amount of sample is not known accurately, sensitivity on integrator or recorder is by trial and error.

Preparation of Sulphamoyl Chloride

Sulphamoyl chloride was prepared by the reaction of chlorosulphonyl isocyanate with formic acid according to the method of Appel and Berger. To anhydrous sulphur-free toluene (150 ml) chlorosulphonyl isocyanate (25 g., 177 mmol) was added at 0° C. under an atmosphere of N₂. After stirring, formic acid (6.0 ml, 156 mmol) was added dropwise at 0° C. under N₂. The resulting white light emulsion was kept stirring overnight and the toluene removed by using a water vacuum pump to give a light yellow crude of sulphamoyl chloride (16.24 g, 79%). A standard solution (0.70 M) of sulphamoyl chloride was then prepared by dissolving the crude crystalline product in anhydrous sulphur-impurities-free toluene and stored in the dark under N₂.

Toluene used for preparing sulphamoyl chloride solution was purified according to the method described. Cold toluene (1–3 liters) was placed in a separating funnel and washed with cold conc. H₂SO₄ (100 ml/liters, 3–4 times), once with water, once with aqueous 5% NaOH and again with water until neutral, dried with anhydrous MgSO₄ and sodium metal overnight and then fractionally distilled under N₂ from sodium metal and stored in dark under N₂.

Anhydrous formic acid used for preparing sulphamoyl chloride was purified according the method described. Formic acid (98%) was stirred overnight with boric anhydride and then distilled under N₂, stored in dark under N₂, and for further purification, fractional crystallization using partial freezing was used.

General Synthesis of Flavonoid Sulphamates (1–22)

Starting with the parent compound, the sulphamate derivatives were prepared essentially as previously described (FIG. 13). In this regard, a solution of the appropriate flavone I, isoflavone II or flavanone III in anhydrous DMF was treated with sodium hydride [60% dispersion; 1.2 and 2.5 equiv. for monohydroxyl and dihydroxyl compounds respectively] at 0° C. under an atmosphere of N₂. After evolution of hydrogen had ceased, sulfamoyl chloride in toluene [excess, ca. 3 and 5 equiv. for monohydroxyl and dihydroxyl compounds respectively] was added and the reaction mixture was poured into brine after warming to room temperature overnight and diluting with ethyl acetate. The organic fraction was washed exhaustively with brine, dried (MgSO₄), filtered and evaporated. The crude product obtained was purified by flash chromatography and recrystallisation to give the corresponding sulfamate. All the compounds were fully characterized by spectroscopic and combustion analysis.

Flavone-7-O-sulphamate (1)

7-Hydroxyflavone (500 mg, 2.098 mmol) gave a light yellow residue (606 mg) of which 393 mg in silica (7 g) was fractionated on silica (400 g) with ethyl acetate. Upon evaporation of the first fraction collected gave a white residue (168 mg, 529.4 μmol, 39%) which was recrystallized in ethyl acetate/hexane (1:1) to give () as white crystals (91 mg); m.p.=173° C., the yellow oil formed gave crystals which melted at 210–220° C. (c.f. 7-hydroxyflavone, m.p.=245–247° C.); R_(f)s=0.78 (ethyl acetate) and 0.56 (ethyl acetate/hexane, 4:1); vmax (KBr) 3250, 3080, 1620, 1590, 1390, 1190 cm⁻¹; δ_(H) (400 MHz, acetone-d₆) 6.89 (1H, s, C-3-H), 7.42 (1H, dd, J_(C-8-H, C-6-H)=2.4 Hz and J_(C-5-H, C-6-H)=8.7 Hz, C-6-H), 7.45 (2H, br s, exchanged with D₂O, OSO₂NH₂), 7.61 (3H, m, Ar—H of B-ring), 7.72 (1H, d, J_(C-6-H, C-8-H)=2.1 Hz, C-8-H), 8.10 (2H, m, Ar—H of B-ring) and 8.17 (1H, d, J_(C-6-H, C-5-H)=8.5 Hz, C-5-H). MS: m/z (+ve ion FAB, rel. intensity) 318.0 [100, (M+H)⁺], 255.2(28), 239.1 [20, (M+2H−SO₂NH₂)⁺], 173.2(47), 93.9(32). MS: m/z (−ve ion FAB, rel. intensity) 483.1(30), 468.1 [10, (M−2H+NBA)⁻], 316.0 [100, (M−H)⁻], 237.1 [30, (M−SO₂NH₂)⁻]. Acc. MS: m/z 318.04455, C₁₅H₁₂NO₅S requires 318.04362. Found: C, 56.5; H, 3.44; N, 4.29. C₁₅H₁₁NO₅S requires C, 56.78; H, 3.49; N, 4.41%.

Flavone-6-O-sulphamate (2) and adduct (O)

6-Hydroxyflavone (1.0 g, 4.113 mmol) gave a yellow residue (1.21 g) which was recrystallized in acetone/hexane (3:2) to give (2) as creamy crystals (557 mg). The residue (460 mg) from the mother liquor was fractionated on silica (100 g) with ethyl acetate and upon evaporation of the first fraction collected gave a creamy residue (234 mg, total yield=2.493 mmol, 61%) which was recrystallized in acetone/hexane (2:1) to give a second crop of (2) as white crystals (87 mg); m.p.=190–192° C.; R_(f)s=0.71 (ethyl acetate) and 0.51 (ethyl acetate/hexane, 2:1); vmax (KBr) 3260, 3040, 1620, 1580, 1370, 1180 cm⁻¹; δ_(H) (270 MHz, acetone-d₆) 6.92 (1H, s, C-3-H), 7.36 (2H, br s, exchanged with D₂O, OSO₂NH₂), 7.64 (3H, m, Ar—H of B-ring), 7.75 (1H, dd, J_(C-5-H, C-7-H)=3 Hz and J_(C-8-H, C-7-H)=9 Hz, C-7-H), 7.87 (1H, d, J_(C-7-H, C-8-H)=9 Hz, C-8-H), 8.02 (1H, d, J_(C-7-H, C-5-H)=3 Hz, C-5-H) and 8.13 (2H, m, Ar—H of B-ring). MS: m/z (E.I., 70 eV, rel. intensity) 317.0(11, M⁺), 304.2(6), 238.0 [96, (M+H−SO₂NH₂)⁺], 210.0(16), 187.1(14), 136.0(100), 108.0(26). Acc. MS: m/z 317.02959, C₁₅H₁₁NO₅S requires 317.03579. Found: C, 56.7; H, 3.44; N, 4.31. C₁₅H₁₁NO₅S requires C, 56.78; H, 3.49; N, 4.41%.

The third fraction collected upon evaporation gave a creamy residue (38 mg) which was recrystallized in acetone/hexane (1:1) to give (()) as creamy crystals (17 mg); m.p. 198–199° C.; δ_(H) (270 MHz, acetone-d₆) 3.09 (3H, s, NCH₃), 3.28 (3H, s, NCH₃), 6.91 (1H, s, C-3-H), 7.63 (3H, m, Ar—H of B-ring), 7.71 (1H, dd, J_(C-5-H, C-7-H)=3 Hz and J_(C-8-H, C-7-H)=9 Hz, C-7-H), 7.83 (1H, d, J_(C-7-H, C-8-H)=9 Hz, C-8-H), 7.97 (1H, d, J_(C-7-H, C-5-H)=3 Hz, C-5-H) and 8.13 (3H, m, —CH═N— and Ar—H of B-ring). Found: C, 58.0; H, 4.32; N, 7.39. C₁₈H₁₆N₂O₅S requires C, 58.06; H, 4.33; N, 7.52%.

5-Hydroxyflavone 7-O-sulphamate (3)

5,7-Dihydroxyflavone (1.0 g, 3.933 mmol) gave crude product (1.13 g) which was fractionated on silica (200 g) with chloroform/acetone (8:1). Upon evaporaton, the second fraction gave a yellow residue (0.324 g, 24%) which was recrystallised in ethyl acetate/hexane (1:1) to give 3 as yellow crystals (0.213 g), m.p. 195–200° C. (dec.); R_(f)s=0.21, 0.25 and 0.44 for chloroform/acetone 12:1, 8:1 and 4:1 respectively; vmax (KBr) 3360 (NH₂), 1650 (C═O), 1380 (—SO₂N—) cm.⁻¹. δ_(H) (acetone-d₆.) 6.75, 6.98 and 7.17 (3H, three s, C-3-H, C-6-H, C-8-H), 7.63 (2H, br s, exchanged with D₂O, —OSO₂NH ₂), 7.65 (3H, m, C-3′-H, C-4′-H and C-5′-H), 8.15 (2H, d, J=7.7 Hz, C-2′-H and C-6′-H) and 13.0 (1H, br s, C-5-OH). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 334.1 [100, (M+H)⁺], 255.0 [25, (M+H−SO₂NH₂)⁺], MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 484.1 [14, (M−H+153 (m-NBA))⁻], 332.1 [100, (M−H)⁻], 253.1 [50, (M−H−SO₂NH₂)⁺]. Acc. MS (+ve ion FAB in m-NBA): m/z 334.0392, C₁₅H₁₂NO₆S requires 334.0385. Found: C, 54.0; H, 3.39; N, 4.21. C₁₅H₁₁NO₆S requires C, 54.03; H, 3.33; N, 4.20%.

5-Hydroxy-7-methoxy flavone-6-O-sulphamate (4)

5,6-Dihydroxy-7-methoxy flavone (0.5 g, 1.760 mmol) gave a crude product (0.68 g) which was fractionated on silica (200 g) with chloroform/acetone (8:1), and upon evaporation the second fraction gave a yellow residue (0.463 g, 68%) which was recrystallized in acetone/hexane (1:2) to give 4 as yellow crystals (0.347 g); m.p. 209–212° C.; R_(f)s=0.13, 0.33 and 0.65 for chloroform/acetone 8:1, 4:1 and 2:1 respectively; vmax (KBr) 3380 (—NH₂), 3200 (H-bonded —OH), 1720 (C═O), 1380 (—SO₂N—), cm⁻¹; δ_(H) (DMSO-d₆) 3.95 (3H, s, C-7-OCH ₃), 7.07 (1H, s, C-3-H or C-8-H), 7.12 (1H, s, C-8-H or C-3-H), 7.12 (3H, d, J=7.3 Hz, C-3′-H, C-4′-H, C-5′-H), 7.84 (2H, s, exchanged with D₂O, —OSO₂NH ₂), 8.13 (2H, d, J=7.0 Hz, C-2′-H and C-6′-H) and 13.06 (1H, s, C-5-H). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 364.0 [100, (M+H)⁺], 284.1 [40, (M+H−SO₂NH₂)⁺]. Acc. MS: m/z (FAB)⁺ 364.0511 C₁₆H₁₄NO₇S requires 364.0491. Found C, 52.5; H, 3.68; N, 3.66; C₁₆H₁₃NO₇S requires C, 52.89; H, 3.61; N, 3.85%.

5-Hydroxy-7-methoxy-flavone-4′-O-sulphamate (5)

4′,5-Dihydroxy-7-methoxy flavone (75 mg, 0.264 mmol) gave a crude product (112 mg) which was fractionated on silica (50 g) with chloroform/acetone (8:1), and upon evaporation the second fraction gave a yellow residue (76.5 mg, 68%) which was recrystallized in ethylacetate/hexane (1:2) to give 5 as yellow crystals (55 mg); m.p.=189–192° C.; R_(f)s=0.16 and 0.26 for chloroform/acetone 8:1 and 4:1 respectively, vmax (KBr) 3500 (—NH₂), 3300 (H-bonded —OH), 1660 (C═O), 1380 (—SO₂N—), cm⁻¹. δ_(H) (acetone-d₆) 3.94 (1H, s, C-7-OCH ₃), 6.36 (1H, d, J=2.5 Hz, C-6-H or C-8-H), 6.73 (1H, d, J=2.2 Hz, C-8-H or C-6-H), 6.84 (1H, s, C-3-H) 7.35 (2H, br s, exchanged with D₂O, —SO₂NH ₂), 7.54 (2H, d, J=8.8 Hz, C-3′-H and C-5′-H or C-2′-H and C-6′-H), 8.18 (2H, d, J=8.8 Hz, C-2′-H and C-6′-H or C-3′-H and C-5′-H) and 12.81 (1H, s, C-5-OH). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 364.0 [100, (M+H)⁺], 285.1 [15, (M+H−SO₂NH₂)⁺]. MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 361.9 [95, (M−H)⁻], 283.0 [100, (M−H−SO₂NH₂)⁻]. Acc. MS: m/z (FAB⁺)=364.0500 C₁₆H₁₄NO₇S requires 364.0491 Found C, 51.1; H, 3.69; N, 3.73; C₁₆H₁₃NO₇S requires C, 52.89; H, 3.61; N, 3.85%.

5-Hydroxy 4′,6,7-Trimethoxy flavone-3′-O-sulphamate (6)

3′,5-Dihydroxy-4′,6,7-trimethoxy flavone (75 mg, 0.177 mmol) gave a crude product (103 mg) which was fractionated on silica (50 g) with chloroform/acetone (4:1), and upon evaporation the second fraction gave a yellow residue (58 mg, 56%) which was recrystallized in ethylacetate/hexane (1:2) to give 6 as yellow crystals (32 mg); m.p. 197–199° C.; R_(f)s=0.175 and 0.44 for chloroform/acetone 4:1 and 2:1 respectively; vmax (KBr) 3360 (—NH₂), 3260 (H-bonded —OH), 1620 (C═O), 1370 (—SO₂N—) cm⁻¹; δ_(H) [DMSO-d₆/CDCl₃, (1:5)] 3.88 (3H, s, C-4′-OCH ₃), 3.986 (6H, d, J=4.8 Hz, C-6-OCH ₃ and C-7-OCH ₃), 6.66 (1H, s, C-3-H or C-8-H), 6.71 (1H, s, C-8-H or C-3-H), 7.16 (1H, d, J=8.8 Hz, C-5′-H), 7.63 (2H, s, exchanged with D₂O, —OSO₂NH ₂), 7.86 (1H, d, J=8.8 Hz, C-6′-H), 7.97 (1H, d, J=2.2 Hz, C-2′-H) and 12.74 (1H, s, C-5-OH). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 424.1 [100, (M+H)⁺], 344.1 [10, (M−SO₂NH₂)⁺]. MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 422.1 [100, (M−H)⁻], 344.1 [20, (M−SO₂NH₂)⁻]. Acc. MS: m/z (FAB)⁺ 424.0714 C₁₈H₁₈NO₉S requires 424.0702. Found C, 51.1; H, 3.38; N, 4.33; C₁₈H₁₇NO₉S requires C, 51.06; H, 3.31; N, 4.05%.

4′,5,6,7-Tetramethoxy flavone-3′-O-sulphamate (7)

3′-Hydroxy-4′,5,6,7-tetramethoxy flavone (75 mg, 0.210 mmol) gave a crude product (96 mg) which was fractionated on silica (50 g) with chloroform/acetone (4:1), and upon evaporation the second fraction gave a yellow residue (59 mg, 62%) which was recrystallized in ethylacetate/hexane (1:2) to give 7 as yellow crystals (35 mg); m.p. 138–141° C.; R_(f)s=0.10, 0.27 and 0.59 for chloroform/acetone 8:1, 4:1 and 2:1 respectively; vmax (KBr) 3420 (—NH₂), 1640 (C═O), 1380 (—SO₂N—) cm⁻¹; δ_(H) (acetone-d₆) 3.93 (12H, m, C-5-OCH ₃, C-6-OCH ₃, C-7-OCH ₃, and C-4′-OCH ₃), 6.55 (1H, s, C-3-H) 7.13 (1H, s, C-8-H), 7.23 (2H, br s, exchanged with D₂O, —OSO₂NH ₂) 7.24 (1H, d, J=8.4 Hz, C-5′-H) and 7.93 (2H, m, C-2′-H and C-6′-H). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 437.9 [100, (M+H)⁺], 359.0 [10, (M+H−SO₂NH₂)⁺]. MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 436.0 [100, (M−H)⁺], 357.0 [10, (M−H−SO₂NH₂)⁻]. Acc. MS: m/z (FAB)⁺ 438.0866 C₁₉H₂₀NO₉S requires 438.0859. Found C, 51.5; H, 3.18; N, 4.46; C₁₉H₁₉NO₉S requires C, 52.17; H, 3.20; N, 4.38%.

Flavone-3′,4′-O,O-bisulphamate (8)

3′,4′-dihydroxy flavone (0.45 g, 1.77 mmol) gave a crude product (0.763 g) which was fractionated on silica (200 g) with ethyl acetate/acetone/hexane (2:1:1), and upon evaporation the second fraction gave a pale residue (0.376 g, 49%), which was recrystallized in acetone/hexane (1:2) to give 6 as white crystals (0.173 g); m.p. 170–172° C.; R_(f)s=0.7 and 0.51 for ethyl acetate/acetone 2:1 and ethyl acetate/acetone/hexane 2:1:1 respectively; vmax (KBr) 3240 (—NH₂), 1630 (C═O), 1390 (—SO₂N—) cm⁻¹; δ_(H) [DMSO-d₆/CDCl₃ (1:3)] 6.91 (1H, s, C-3-H), 7.47 (1H, t, J=7.5 Hz, C-6-H) 7.65 (1H, d, J=8.4 Hz, C-6′-H), 7.72 (1H, s, C-8-H), 7.75 (1H, d, J=5.9 Hz, C-7-H), 7.92 (1H, s, C-5-H), 7.97 (4H, br s, exchanged with D₂O, C-3′-OSO₂NH ₂ and C-4′-OSO₂NH ₂), and 8.15 (2H, d, J=7.7 Hz, C-2′-H and C-5′-H). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 413.1 [100, (M+H)⁺], 334.1 [20, (M+H−SO₂NH₂)⁺], 254.1 [20, (M−SO₂NH₂)⁺]. MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 411.0 [100, (M−H)⁻], 332.1 [35, (M−H−SO₂NH₂)⁻], 253.1 [40, (M−H−SO₂NH₂)⁻]. Acc. MS: m/z 413.0120 C₁₅H₁₃N₂O₈S₂ requires 413.0113. Found C, 44.3; H, 3.3; N, 6.21; C₁₅H₁₂N₂O₈S₂ requires C, 43.69; H, 2.93; N, 6.79%.

5-Hydroxy flavone-4′,7-O,O-bisulphamate (9)

4′,5,7-Trihydroxy flavone (72 mg, 0.266 mmol) gave a crude product (117 mg) which was fractionated on silica (50 g) with chloroform/acetone (2:1) and upon evaporation the second fraction gave a yellow residue (70 mg, 60%) which was recrystallized in acetone/chloroform (1:2) to give 9 as yellow crystals (45 mg); m.p.>198° C. (dec.); R_(f)s=0.083 and 0.385 for chloroform/acetone 4:1 and 2:1 respectively; vmax (KBr) 3380 (—NH₂), 3260 (H-bonded —OH), 1650 (C═O), 1390 (—SO₂N—) cm⁻¹; δ_(H) (DMSO-d₆) 6.76 (1H, s, C-3-H), 7.2 (1H, s, C-6-H or C-8-H), 7.23 (1H, s, C-8-H or C-6-H), 7.5 (2H, d, J=8.4 Hz, C-3′-H and C-5′-H), 8.27 (2H, d, J=9.1 Hz, C-2′-H and C-6′-H), 8.38 (4H, br s, exchanged with D₂O, C-4′-OSO₂NH ₂ and C-7-OSO₂NH ₂) and 12.87 (1H, s, C-5-OH). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 428.7 [80, (M+H)⁺], 349.8 [25, (M−SO₂NH₂)⁺], 270.9 [25, (M−SO₂NH₂)⁺]. MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 426.7 [80, (M−H)⁻], 347.8 [80, (M−H−SO₂NH₂)⁻], 268.9 [50, (M−H−SO₂NH₂)⁻]. Found C, 40.6; H, 2.78; N, 6.31; C₁₅H₁₂N₂O₉S₂ requires C, 42.06; H, 2.82; N, 6.54%.

5-Hydroxy flavone-3,7-O,O-bisulphamate (10)

3,5,7-Trihydroxy flavone (75 mg, 0.277 mmol) gave a crude product (0.123 g) which was fractionated on silica (50 g) with chloroform/acetone (4:1), and upon evaporation the third fraction gave a yellow residue (58 mg, 47%) which was recrystallized in ethylacetate/hexane (1:2) to give 10 as yellow crystals (31 mg); m.p. 171–173° C.; R_(f)s=0.26 and 0.54 for chloroform/acetone 4:1 and 2:1 respectively; vmax (KBr) 3360 (—NH₂), 3260 (H-bonded —OH), 1660 (C═O), 1390 (—SO₂N—) cm⁻¹; δ_(H) (acetone-d₆) 6.81 (1H, d, J=2.2 Hz, C-6-H), 7.21 (1H, d, J=2.2 Hz, C-8-H), 7.31 (2H, br s, exchanged with D₂O, —OSO₂NH ₂), 7.54 (2H, br s, exchanged with D₂O, —OSO₂NH ₂), 7.64 (3H, m, C-3′-H, C-4′-H and C-5′-H), 8.14 (2H, m, C-2′-H and C-6′-H) and 12.29 (1H, s, C-5-OH). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 428.9 [100, (M+H)⁺], 348.9 [50, (M−SO₂NH₂)⁺], 270.0 [25, (M−SO₂NH₂)⁺]. MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 426.9 [85, (M−H)⁻], 347.9 [100, (M−H−SO₂NH₂)⁻], 269.0 [80, (M−SO₂NH₂)⁻]. Acc. MS: m/z 429.0086 C₁₅H₁₃N₂O₉S₂ requires 429.0063. Found C, 42.11; H, 3.06; N, 6.13; C₁₅H₁₂N₂O₉S₂ requires C, 42.06; H, 2.82; N, 6.54%.

5-Hydroxy-4′-methoxy flavone-3,7-O,O-bisulphamate (11)

3,5,7-Trihydroxy-4′-trimethoxy flavone (0.075 g, 0.250 mmol) gave a crude product (0.116 g) which was fractionated on silica (50 g) with chloroform/acetone (4:1), and upon evaporation the third fraction gave a yellow residue (0.054 g, 47%) which was recrystallized in acetone/hexane (1:2) to give 11 as yellow crystals (29 mg); m.p.>192° C. (dec.); R_(f)s=0.19 and 0.55 for chloroform/acetone 4:1 and 2:1 respectively; vmax (KBr) 3420 (—NH₂), 1620 (C═O), 1360 (—SO₂N—) cm⁻¹; δ_(H) [acetone-d₆) 3.94 (3H, s, C-4′-OCH ₃), 6.80 (1H, s, C-6-H,), 7.12 (1H, s, C-8-H), 7.16 (2H, d, J=8.8 Hz, C-3′-H and C-5′-H), 7.39 (2H, br s, exchanged with D₂O, —OSO₂NH ₂), 7.50 (2H, s, exchanged with D₂O, —OSO₂NH ₂), 8.2 (2H, d, J=6.7 Hz, C-2′-H and C-6′-H) and 12.43 (1H, br s, C-5-OH). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 459.1 [100, (M+H)⁺], 379.1 [55, (M−SO₂NH₂)⁺], 300.1 [15, (M−SO₂NH₂)⁻]. MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 456.2 [20, (M−H)⁻], 378.1 [100, (M−H−SO₂NH₂)⁻], 299.1 [70, (M−H−SO₂NH₂)⁻]. Acc. MS: m/z 459.0174 C₁₆H₁₅N₂O₁₀S₂ requires 459.0168. Found C, 41.98; H, 3.06; N, 6.11; C₁₆H₁₄N₂O₁₀S₂ requires C, 41.92; H, 3.08; N, 6.11%.

5-Hydroxy-3′,4′,5′-Trimethoxy flavone-3,7-O,O-bisulphamate (12) and 5,7-Dihydroxy-3′,4′,5′-Trimethoxy flavone-3-O-sulphamate (13)

3,5,7-Trihydroxy-3′,4′,5′-trimethoxy flavone (0.2 g, 0.555 mmol) gave a crude product (0.231 g) which was fractionated on silica (100 g) with chloroform/acetone (4:1), and upon evaporation the third fraction gave a yellow residue (0.108 g, 51%) which was recrystallized in acetone/hexane (1:2) to give 12 as yellow crystals (69 mg); m.p. 124–126° C.; R_(f)s=0.19 and 0.53 for chloroform/acetone 4:1 and 2:1 respectively; vmax (KBr) 3360 (—NH₂), 3260 (H-bonded —OH), 1660 (C═O), 1430 (—SO₂N—) cm⁻¹; δ_(H) [DMSO-d₆/CDCl₃, (1:3)] 3.91 (3H, s, C-4′-OCH ₃), 3.95 (6H, s, C-3′-OCH ₃ and C-5′-OCH ₃), 6.83 (1H, d, J=1.8 Hz, C-6-H,), 7.12 (1H, d, J=2.2 Hz, C-8-H), 7.39 (2H, s, C-2′-H and C-6′-H), 7.72 (2H, s, exchanged with D₂O, —OSO₂NH ₂), 8.06 (2H, s, exchanged with D₂O, —OSO₂NH ₂) and 12.2 (1H, s, C-5-OH). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 519.1 [100, (M+H)⁺], 439.1 [60, (M−SO₂NH₂)⁺], 360.1 [10, (M−SO₂NH₂)⁻]. MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 517.1 [85, (M−H)⁻], 438.1 [100, (M−H−SO₂NH₂)⁻], 359.1 [80, (M−H−SO₂NH₂)⁻]. Acc. MS: m/z 519.0387 C₁₈H₁₉N₂O₁₂S₂ requires 519.0379. Found C, 42.3; H, 3.71; N, 5.11; C₁₈H₁₈N₂O₁₂S₂ requires C, 41.7; H, 3.5; N, 5.4%.

The second fraction was collected and upon evaporation gave a yellow residue (53 mg, 30%) which was recrystallized in ethylacetate/hexane (1:2) to give 13 as yellow crystals (26 mg); m.p. 189–192° C., R_(f)s=0.10, 0.32 and 0.62 for chloroform/acetone 8:1, 4:1 and 2:1 respectively; vmax (KBr) 3500 (—NH₂), 1660 (C═O), 1390 (—SO₂N—) cm⁻¹; δ_(H) [DMSO-d₆/CDCl₃, (1:1)] 3.84 (3H, s, C-4′-OCH ₃), 3.91 (6H, s, C-3′-OCH ₃ and C-5′-OCH ₃), 6.27 (1H, s, C-6-H), 6.51 (1H, s, C-8-H), 7.33 (2H, s, C-2′-H and C-6′-H), 7.84 (2H, br s, exchanged with D₂O, —OSO₂NH ₂), 10.8 (1H, s, C-7-OH) and 12.43 (1H, s, C-5-OH). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 440.1 [100, (M+H)⁺], 360.1 [80, (M−SO₂NH₂)⁺]. MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 438.1 [100, (M−H)⁻], 359.1 [80, (M−H−SO₂NH₂)⁻]. Acc. MS: m/z 440.0633 C₁₈H₁₈NO₁₀S requires 440.0651. Found C, 48.3; H, 3.89; N, 3.11; C₁₈H₁₇NO₁₀S requires C, 49.2; H, 3.9; N, 3.19%.

3′,4′,5′-Trimethoxy flavone-3,7-O,O-bisulphamate (14) and 7-Hydroxy 3′,4′,5′-Trimethoxy flavone-3-O-sulphamate (15)

3,7-Dihydroxy-3′,4′,5′-trimethoxy flavone (0.2 g, 0.581 mmol) gave a crude product (0.285 g) which was fractionated on silica (200 g) with chloroform/acetone (4:1), and upon evaporation the third fraction gave a yellow residue (0.212 g, 74%) which was recrystallized in acetone/hexane (1:2) to give 14 as light yellow crystals (123 mg); m.p. 182–184° C.; R_(f)s=0.14 and 0.21 for chloroform/acetone 4:1 and 2:1 respectively; vmax (KBr) 3480 (—NH₂), 1610 (C═O), 1420 (—SO₂N—) cm⁻¹; δ_(H) (acetone-d₆) 3.85 (3H, s, C-4′-OCH ₃), 3.94 (6H, s, C-3′-OCH ₃ and C-5′-OCH ₃), 7.48 (3H, m, C-6-H, C-2′-H and C-6′-H), 7.69 (4H, br s, exchanged with D₂O, C-3-OSO₂NH ₂ and C-7-OSO₂NH ₂), 7.79 (1H, s, C-8-H) and 8.27 (1H, d, J=8.3 Hz, C-5-H). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 502.9 [100, (M+H)⁺], 423.0 [60, (M−SO₂NH₂)⁺], 344.1 [10, (M−SO₂NH₂)⁺]. MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 501.0 [100, (M−H)⁻], 422.0 [80, (M−H−SO₂NH₂)⁻], 343.0 [75, (M−SO₂NH₂)⁻]. Acc. MS: m/z 503.0444 C₁₈H₁₉N₂O₁₁S₂ requires 503.0430. Found C, 42.2; H, 3.61; N, 5.38; C₁₈H₁₈N₂O₁₁S₂ requires C, 43.03; H, 3.61; N, 5.58%.

The second fraction was collected and upon evaporation gave a light yellow residue (12 mg) to give 15; m.p 159–162° C.; R_(f)s=0.23 and 0.50 for chloroform/acetone 4:1 and 2:1 respectively; vmax (KBr) 3500 (—NH₂), 3250 (H-bonded —OH), 1620 (C═O), 1420 (—SO₂N—) cm ⁻¹. MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 424.0 [100, (M+H)⁺], 344.0 [70, (M+H−SO₂NH₂)⁺]. MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 422.0 [100, (M−H)⁻], 343.0 [70, (M−H−SO₂NH₂)⁻]. Acc. MS: m/z (FAB)⁺ 424.0702 C₁₈H₁₈NO₉S requires 424.0703.

5-Hydroxy-4′-methoxyisoflavone 7-O-sulphamate (16)

5,7-Dihydroxy-4′-methoxyisoflavone (0.8 g, 2.817 mmol) gave crude product (0.65 g) which was fractionated on silica (200 g) with chloroform/acetone (8:1). Upon evaporation, the second fraction gave a yellow residue (0.266 g, 26%) which was recrystallised in ethyl acetate/hexane (1:1) to give 16 as yellow crystals (0.211 g), m.p. 184–188° C.; R_(f)s=0.22 and 0.59 for chloroform/acetone 8:1 and 4:1 respectively; vmax (KBr) 3300 (—NH₂), 1660 (C═O), 1400 (—SO₂N—) cm⁻¹; δ_(H) (acetone-d₆) 3.86 (3H, s, -C-4′-OCH ₃), 6.75 (1H, d, J=2.2 Hz, C-6-H or C-8-H), 7.04 (3H, m, C-6-H or C-8-H, and C-3′-H and C-5′-H), 7.49 (2H, br s, exchanged with D₂O, —OSO₂NH ₂), 7.58 (2H, d, J=7.0 Hx, C-2′-H and C-6′-H), 8.41 (1H, s, C-2-H), 13.05 (1H, br s, exchanged with D₂O, C-5-OH). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 364.0 [100, (M+H)⁺], 284.1 [12, (M−SO₂NH₂)⁺]. MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 515.1 [12, (M−H+m-NBA)⁻], 362.1 [100, (M−H)⁻], 283.1 [70, (M−H−SO₂NH₂)⁻]. Acc. MS (+ve ion FAB in m-NBA): m/z 364.0494, C₁₆H₁₄NO₇S requires 364.0491. Found: C, 52.8; H, 3.65; N, 3.81. C₁₆H₁₃NO₇S requires C, 52.89; H, 3.61; N, 3.85%.

5-Hydroxy isoflavone-4′,7-O,O-bisulphamate (17) and 5,7-Dihydroxy isoflavone-4′-O-sulphamate (16)

4′,5,7-Trihydroxy isoflavone (0.5 g, 1.85 mmol) gave a crude product (0.65 g) which was fractionated on silica (200 g) with chloroform/acetone (4:1), and upon evaporation the third fraction gave light yellow residue (0.329 g, 51%) which was recrystallized in ethylacetate/hexane (1:2) to give 17 as beige crystals (0.197 g); m.p.=>198° C. (dec.); R_(f)s=0.14 and 0.24 for chloroform/acetone 4:1 and 2:1 respectively; vmax (KBr) 3460 (—NH₂), 1650 (C═O), 1400 (—SO₂N—) cm⁻¹; δ_(H) (acetone-d₆) 6.78 (1H, d, J=2.2 Hz, C-6-H or C-8-H), 7.03 (1H, d, J=2.2 Hz, C-8-H or C-6-H) 7.4 (4H, br s, exchanged with D₂O, C-4′-OSO₂NH ₂ and C-7-OSO₂NH ₂), 7.43 (2H, d, J=8.4 Hz, C-3′-H and C-5′-H or C-2′-H and C-6′-H),, 7.72 (2H, d, J=8.4 Hz, C-2′-H and C-6′-H or C-3′-H and C-5′-H), 8.51 (1H, s, C-2-H) and 12.93 (1H, s, C-5-OH). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 428.9 [100, (M+H)⁺], 350.0 [20, (M+H−SO₂NH₂)⁺], 272.1 [30, (M−H−SO₂NH₂)³⁰ ]. MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 426.9 [100, (M−H)⁻], 347.9 [95, (M−H−SO₂NH₂)⁻], 269.0 [30, (M−H−SO₂NH₂)⁻]. Acc. MS: m/z (FAB)⁺ 429.0083 C₁₅H₁₃N₂O₉S₂ requires 429.0063. Found C, 42.0; H, 2.91; N, 6.45; C₁₅H₁₂N₂O₉S₂ requires C, 42.06; H, 2.82; N, 6.54%.

The second fraction was collected and upon evaporation gave light yellow residue (0.112 g, 17%) which was recrystallized in ethylacetate/hexane (1:3) to give 18 as a pale white crystals (0.068 g); m.p.=189–192° C.; R_(f)s=0.23 and 0.33 for chloroform/acetone 4:1 and 2:1 respectively; vmax (KBr) 3500−3300 (—NH₂), 3200 (H-bonded —OH), 1680 (C═O), 1610, 1400 (—SO₂N—) cm⁻¹; δ_(H) (acetone-d₆) 6.32 (1H, d, J=2.2 Hz, C-6-H or C-8-H), 6.46 (1H, d, J=2.2 Hz, C-8-H or C-6-H), 7.32 (2H, br s, exchanged with D₂O, —SO₂NH ₂), 7.42 (2H, t, J=8.4 Hz, C-3′-H and C-5′-H or C-2′-H and C-6′-H), 7.69 (2H, d, J=8.4 Hz, C-2′-H and C-6′-H or C-3′-H and C-5′-H) 8.31 (1H, s, C-2-H), 9.53 (1H, s, C-7-OH) and 12.9 (1H, s, C-5-OH). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 350.0 [100, (M+H)⁺], 271.1 [15, (M+H−SO₂NH₂)⁺]. MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 347.9 [100, (M−H)⁻], 269.0 [20, (M−H−SO₂NH₂)⁻]. Acc. MS: m/z (FAB)⁺ 350.0347 C₁₅H₁₂NO₇S requires 350.0335. Found C, 51.0; H, 3.16; N, 3.90; C₁₅H₁₁NO₇S requires C, 51.58; H, 3.17; N, 4.01%.

Isoflavone-4′,7-O,O-bisulphamate (19)

4′,7-Dihydroxy isoflavone (0.45 g, 1.77 mmol) gave a crude product (0.769 g) which was fractionated on silica (200 g) with chloroform/acetone (4:1), and upon evaporation the second fraction gave a pale white residue (0.553 g, 72%) which was recrystallized in acetone/hexane (1:2) to give 19 as white crystals (0.327 g); m.p.>195° C. (dec.), R_(f)s=0.21 and 0.40 for chloroform/acetone 4:1 and 2:1 respectively; vmax (KBr) 3400 (—NH₂), 1640 (C═O), 1360 (—SO₂N—) cm⁻¹; δ_(H) (DMSO-d₆) 7.37 (2H, d, J=8.8 Hz, C-3′-H and C-5′-H or C-2′-H, and C-6′-H), 7.42 (1H, dd, J_(C-6-H, C-8-H)=2.2 Hz, J=_(C-6-H, C-5-H)=8.8 Hz, C-6-H), 7.7 (2H, d, J=8.8 Hz, C-2′-H and C-6′-H or C-3′-H, and C-5′-H), 8.09 (2H, br s, exchanged with D₂O, —OSO₂NH ₂), 8.24 (1H, d, J=8.8 Hz, C-5-H), 8.36 (2H, br s, exchanged with D₂, —OSO₂NH ₂), 8.63 (1H, s, C-2-H). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 412.9 [100, (M+H)⁺], 334.0 [25, (M+H−SO₂NH₂)⁺], 255.1 [20, (M+H−SO₂NH₂)⁺]. MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 410.9 [100, (M−H)⁻], 332.0 [70, (M−H−SO₂NH₂)⁻], 253.0 [30, (M−H−SO₂NH₂)⁻]. Acc. MS: m/z (FAB)⁺ 413.0119 C₁₅H₁₃N₂O₈S₂ requires 413.0113. Found C, 44.0; H, 2.94; N, 6.62; C₁₅H₁₂N₂O₈S₂ requires C, 43.69; H, 2.93; N, 6.79%.

5,7-Dihydroxyflavanone 4′-O-sulphamate (20)

4′,5,7-Trihydroxyflavanone (1.0 g, 3.675 mmol) gave crude product (0.965 g) which was fractionated on silica (200 g) with chloroform/acetone (2:1) and then (4:1) and upon evaporation, the second fraction gave a pale yellow oil (0.345 g, 34%) which solidified on standing. Subsequent recrystallisation of this solid in ethylacetate/hexane (1:1) gave 20 as white crystals (0.259 g), m.p. 211–213° C.; R_(f)s=0.21 (chloroform/acetone, 4:1); vmax (KBr) 3420 (—NH₂), 3260 (H-bonded —OH), 1640 (C═O), 1380 (—SO₂N—) cm⁻¹; δ_(H) (acetone-d₆) 2.84 (1H, dd, J_(AB)=17.4 Hz and J_(ax,eq)=3.1 Hz, C-3-H _(B)), 3.19 (1H, dd, J_(BA)=16.9 Hz and J_(ax,ax)=12.8 Hz, C-3-H_(A)), 5.62 (1H, dd, J_(ax,eq)=3.1 Hz and J_(ax.ax)=12.8 Hz, C-2-H), 5.98 (1H, d, J=2.0 Hz, C-6-H or C-8-H), 6.01 (1H, d, J=2.0 Hz, C-6-H or C-8-H), 7.20 (2H, br s, exchanged with D₂O, —OSO₂NH ₂), 7.40 (2H, d, J=8.7 Hz, C-2′-H and C-6′-H or C-3′-H and C-5′-H), 7.66 (2H, d, J=8.7 Hz, C-3′-H and C-5′-H or C-2′-H and C-6′-H), 9.65 (1H, br s, C-7-OH) and 12.15 (1H, s, C-5-OH). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 352.0 [100, (M+H)⁺], 272.1 [14, (M−SO₂NH₂)⁺]. MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 504.1 [20, (M+NBA)⁻], 350.1 [100, (M−H)⁻], 271.1 [45, (M−H−SO₂NH₂)⁻]. Acc. MS (+ve ion FAB in m-NBA): m/z 352.0496 C₁₅H₁₄NO₇S requires 352.0491. Found: C, 51.1; H, 3.68; N, 3.98. C₁₅H₁₃NO₇S requires C, 51.28; H, 3.73; N, 3.99%.

5-Hydroxy 4′-methoxy flavanone-3′,7-O,O-bisulphamate (21)

4′-Methoxy-3′,5,7-trimethoxy flavanone (1.0 g, 2.637 mmol) gave a crude product (1.672 g) which was fractionated on silica (200 g) with chloroform/acetone (2:1), and upon evaporation the second fraction gave a yellow residue (0.715 g, 43%) which was recrystallized in ethylacetate/hexane (1:2) to give 20 as yellow crystals (0.513 g); m.p. 186–188° C.; R_(f)s=0.13 and 0.35 for chloroform/acetone 4:1 and 2:1 respectively; vmax (KBr) 3380 (—NH₂), 3280 (H-bonded —OH), 1640 (C═O), 1390 (—SO₂N—) cm⁻¹; δ_(H) (acetone-d₆) 2.92 (1H, m, C-3-H), 3.36 (1H, m, C-3-H), 3.91 (3H, s, C-4′-OCH ₃), 5.68 (1H, dd, J=12.8 Hz, C-2-H), 6.46 (1H, s, C-6-H or C-8-H), 6.49 (1H, s, C-8-H or C-6-H), 7.07 (2H, br s, exchanged with D₂O, —OSO₂NH ₂), 7.24 (1H, d, J=8.4 Hz, C-5′-H), 7.50 (2H, br s, exchanged with D₂O, —OSO₂NH ₂), 7.55 (1H, dd, J_(C-6′-H, C-5′-H)=8.4 Hz, J_(C-6′-H, C-2′-H)=2.2 Hz, C-6′-H), 7.75 (1H, d, J=2.2 Hz, C-2′-H) and 12.02 (1H, s, C-5-OH). MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 460.9 [100, (M+H)⁺], 381.9 [20, (M+H−SO₂NH₂)⁺], 303.0 [25, (M+H−SO₂NH₂)⁺]. MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 458.9 [100, (M−H)⁻], 379.9 [20, (M−H−SO₂NH₂)⁻], 301.0 [20, (M−H−SO₂NH₂)]. Acc. MS: m/z (FAB)⁺ 461.0337 C₁₆H₁₇N₂O₁₀S₂ requires 416.0325. Found C, 41.0; H, 3.51; N, 5.97; C₁₆H₁₆N₂O₁₀S₂ requires C, 41.74; H, 3.50; N, 6.08%.

(±) 7,4′-Dihydroxy isoflavane (Equol) (22a)

A suspention of Palladium-on-charcoal (10%, 2.2 g) in glacial acetic acid (15 ml) was treated with oxygen for three days. The suspention catalyst was added to the solution of 4′,7-dihydroxy isoflavone (0.5 g, mmol) in diglume (60 ml). After 30 min. of catalytic hydrogenation at atmospheric pressure, the solution was filtered and washed with diglume and hot acetic acid. The combined filtrate were evaporoted by using water vacuum pump followed by high vacuum pump. The curde was dissolved in ethylacetate and wished with sodium bicarbonate (5%) and with water till neutral, dried (MgSO₄) filtred and evaporeted to give pale white crude (0.385 g) which was recrystallized in aquoes ethanol to give 22a as white crystals (0.361 g), m.p. 156–158° C. (lit. 158° C.). R_(f)s=IR (KBr) 3380−2720 cm⁻¹. δ_(H) (acetone-d₆) 2.89 (2H, m, C-4-H ₂), 3.1 (1H, m, C-3-H), 3.94 (1H, t, J=10.38 Hz, C-2-H _(A)), 4.18 (1H, m, C-2-H _(E)), 6.29 (1H, d, J_(C-8-H & C-6-H)=2.44 Hz, C-8-H), 6.37 (1H, dd, J_(C-6-H & C-7-H)=8.24 Hz, J_(C-6-H & C-8-H)=2.44 Hz, C-6-H), 6.82 (2H, dd, J_(C-)3′-H & C-2′-H=8.55 Hz, J_(C-)3′ & C-5-H=2.74 Hz, C-3′-H and C-5′-H or C-2′-H and C-6′-H), 6.89 (1H, d, J_(C-5-H & C-6-H)=8.24 Hz, C-5-H), 7.16 (2H, dd, J_(C-2′-H & C-5′-H)=8.24 Hz, J_(C-2′-H & C-6′-H)=2.74 Hz, C-2′-H and C-6′-H or C-3′-H and C-5′-H), 8.15 (1H, br s, C-7-OH or C-4′-OH) and 828 (1H, br s, C-4′-OH or C-7-OH).

¹³CNMR (acetone-d₆)

MS: m/z (+ve ion FAB in m-NBA, rel. intensity) 242.1 [100, (M)⁺], [, (M−SO₂NH₂)⁺]. MS: m/z (−ve ion FAB in m-NBA, rel. intensity) 394.2 [50, (M−H+NBA)⁻], 241.2 [100, (M−H)⁻]. Acc. MS (+ve ion FAB in m-NBA: m/z 242.094 C₁₅H₁₅O₃ requires 243.1021. Found: C,; H, 4. C₁₅H₁₄O₃ requires C, 74.36; H, 5.82%.

(±) Isoflavane-7,4′-O,O-bisulphamate (22)

(±) Equol (0.15 g, 0.619 mmol) gave crude product (0.254 g) which was fractionated on silica (100 g) with chloroform/acetone (8:1) and then (4:1) upon evaporation, the second fraction gave brown residue (96 mg, 38%) which was recrystallisation in acetone/hexane (1:2) gave 22 as light brown crystals (61 mg), m.p. ° C.; R_(f)s=(chloroform/acetone, 4:1); vmax (KBr) 3160 (—NH₂), 1380 (—SO₂N—) cm⁻¹; δ_(H) (acetone-d₆) 3.1 (2H, m, C-4-H ₂), 3.13 (1H, m, C-3-H), 4.12 (1H, t, J=10.38 Hz, C-2-H _(A)), 4.35 (1H, dd, J₁=3.05 Hz and J₂=10.68 Hz C-2-H _(E)), 6.78 (1H, d, J_(C-8-H & C-6-H)=2.44 Hz, C-8-H), 6.84 (1H, dd, J_(C-6-H & C-7-H)=8.44 Hz, J_(C-6-H & C-8-H)=2.44 Hz, C-6-H), 7.13 (4H, br s, exchanged with D₂O, C-7-OSO₂NH ₂ & C-4′-OSO₂NH ₂), 7.18 (1H, d, J_(C-5-H & C-6-H)=8.24 Hz, C-5-H), 7.32 (2H, m, C-3′-H and C-5′-H or C-2′-H and C-6′-H), 7.44 (2H, m, C-2′-H and C-6′-H or C-3′-H and C-5′-H), MS: m/z (+ve ion FAB in m-NBA, rel. intensity) [100, (M+H)⁺], [, (M−SO₂NH₂)⁺]. MS: m/z (−ve ion FAB in m-NBA, rel. intensity) [, (M+NBA)⁻], [100, (M−H)⁻], [, (M−H−SO₂NH₂)⁻]. Acc. MS (+ve ion FAB in m-NBA): m/z C₁₅H₁₇N₂O₇S₂ requires 401.04772. Found: C, 44.6; H, 4.0; N, 6.54. C₁₅H₁₆N₂O₇S₂ requires C, 44.99; H, 4.03; N, 7.0%.

Biology

Sulphatase Inhibition: Sulphatase inhibition was accessed by using intact MCF-7 breast cancer cells as described previously.

Aromatase Inhibition: Placental microsomes were used to access the aromatase inhibitory properties of the flavonoid sulphamates using the tritiated water release assay¹¹. Placental microsomes (200 μg protein) were incubated with [1β-³H] androstenedione (60 nM) and NADPH (1 μM) in the absence or presence of inhibitor (10 μM). 

1. A sulphamate compound of general formula XII;

wherein A represents the first ring structure, B represents the third ring structure, D represents the second ring structure, E is a bond, X is CH₂ or C═O, and Y is CH₂ or O; and wherein ring structure has bound thereto a sulphamate group.
 2. A compound according to claim 1 wherein if the sulphamate group on the compound were replaced with a sulphate group to form a sulphate compound, then that sulphate compound would be hydrolysable by an enzyme having steroid sulphatase (E.C.3.1.6.2) activity.
 3. A compound according to claim 1 wherein the first ring structure and the second ring structure are substituted.
 4. A compound according to claim 1 wherein the third ring structure is a heterogeneous ring structure.
 5. A compound according to claim 1 wherein X is C═O.
 6. A compound according to claim 1 wherein Y is O.
 7. A compound according to claim 1 wherein the compound of the present invention is a sulphamate of any one of a flavone, an isoflavone or a flavanone.
 8. A compound according to claim 7 wherein the compound is any one of a compound of the general formula IV, a compound of the general formula V or a compound of the general formula VI;

wherein R₁–R₁₂ are independently selected from H, OH, a halogen, an amine, an amide, a suplhonamine, a sulphonamide, any other sulphur containing group, a saturated or unsaturated C₁₋₁₀ alkyl, an aryl group, a saturated or unsaturated C₁₋₁₀ ether, a saturated or unsaturated C₁₋₁₀ ester, and a phosphorous containing group; and wherein at least one of R₁–R₁₂ is a sulphamate group.
 9. A compound according to claim 8 wherein the sulphamate group has the general formula of OSO₂NR₁₃R₁₄ wherein R₁₃ and R₁₄ are independently selected from H, OH, a halogen, a saturated or unsaturated C₁₋₁₀ alkyl, an aryl group, a saturated or unsaturated C₁₋₁₀ ether, a saturated or unsaturated C₁₋₁₀ ester.
 10. A compound according to claim 8 wherein R₁–R₁₂ are independently selected from H, OH, OSO₂NR₁₃R₁₄, O—CH₃, wherein at least one of R₁–R₁₂ is OSO₂NR₁₃R₁₄, and wherein R₁₃ and R₁₄ are independently selected from H, OH, a halogen, a saturated or unsaturated C₁₋₁₀ alkyl, an aryl group, a saturated or unsaturated C₁₋₁₀ ether, a saturated or unsaturated C₁₋₁₀ ester.
 11. A compound according to claim 8 wherein R₁₃ and R₁₄ are H.
 12. A compound according to claim 9 wherein R₁₃ and R₁₄ are H.
 13. A compound according to claim 10 wherein R₁₃ and R₁₄ are H.
 14. A compound according to claim 1 wherein the compound is a sulphamate of any one of the flavones of formula VII, the isoflavones of formula VIII or the flavanones of formula IX

wherein R₁–R₄ are independently selected from H, OH, a halogen, an amine, an amide, a sulphonamine, a sulphonamide, any other sulphur containing group, a saturated or unsaturated C₁₋₁₀ alkyl, an aryl group, a saturated or unsaturated C₁₋₁₀ ether, a saturated or unsaturated C₁₋₁₀ ester, and a phosphorous containing group; and wherein at least one of R₁–R₄ is a sulphamate group.
 15. A compound according to claim 14 wherein the sulphamate group is on R₄.
 16. A compound according to claim 1 wherein the compound is a flavanoid sulphamate.
 17. A composition for inhibiting oestrone sulphatase activity and aromatase activity comprising a compound according to claim
 1. 18. A pharmaceutical composition comprising a compound according to claim 1; and a pharmaceutically acceptable carrier, excipient or diluent.
 19. A pharmaceutical composition comprising a compound according to claim 8; and a pharmaceutically acceptable carrier, excipient or diluent.
 20. A pharmaceutical composition comprising a compound according to claim 11; and a pharmaceutically acceptable carrier, excipient or diluent. 